Refactor the diagnostic renderer to avoid printing trailing whitespace

experimental/parser/testdata/lexer/braces/interleaved.proto.stderr.txt

@@ -1,6 +1,6 @@
 error: encountered unmatched `[` delimiter
   --> testdata/lexer/braces/interleaved.proto:2:5
-   | 
+   |
  2 |     [
    |     ^ expected a closing `]`
  3 | }

experimental/parser/testdata/lexer/braces/stray-close.proto.stderr.txt

@@ -1,6 +1,6 @@
 error: encountered unmatched `{` delimiter
   --> testdata/lexer/braces/stray-close.proto:1:1
-   | 
+   |
  1 | {
    | ^ expected a closing `}`
  2 |     ]

experimental/parser/testdata/lexer/braces/stray-open.proto.stderr.txt

@@ -1,6 +1,6 @@
 error: encountered unmatched `[` delimiter
   --> testdata/lexer/braces/stray-open.proto:2:5
-   | 
+   |
  2 |     [
    |     ^ expected a closing `]`
 

experimental/parser/testdata/lexer/braces/unclosed.proto.stderr.txt

@@ -1,6 +1,6 @@
 error: encountered unmatched `(` delimiter
   --> testdata/lexer/braces/unclosed.proto:1:1
-   | 
+   |
  1 | (
    | ^ expected a closing `)`
 

experimental/parser/testdata/lexer/braces/unopened.proto.stderr.txt

@@ -1,6 +1,6 @@
 error: encountered unmatched `)` delimiter
   --> testdata/lexer/braces/unopened.proto:1:1
-   | 
+   |
  1 | )
    | ^ expected a closing `(`
 

experimental/parser/testdata/lexer/comments/nested.proto.stderr.txt

@@ -1,6 +1,6 @@
 error: encountered unmatched `*/` delimiter
   --> testdata/lexer/comments/nested.proto:4:1
-   | 
+   |
  4 | */
    | ^^ expected a closing `/*`
    = note: Protobuf does not support nested block comments

experimental/parser/testdata/lexer/comments/unterminated.proto.stderr.txt

@@ -1,6 +1,6 @@
 error: encountered unmatched `/*` delimiter
   --> testdata/lexer/comments/unterminated.proto:1:1
-   | 
+   |
  1 | /*
    | ^^ expected a closing `*/`
 

experimental/parser/testdata/lexer/idents/non-ascii.proto.stderr.txt

@@ -1,31 +1,31 @@
 error: unrecognized token
   --> testdata/lexer/idents/non-ascii.proto:1:7
-   | 
+   |
  1 | kitty_🐈<U+200D>⬛
-   |       ^^^^^^^^^^^^ 
+   |       ^^^^^^^^^^^^
 
 error: non-ASCII identifiers are not allowed
   --> testdata/lexer/idents/non-ascii.proto:2:1
-   | 
- 2 | 黑猫 
-   | ^^^^ 
+   |
+ 2 | 黑猫
+   | ^^^^
 
 error: non-ASCII identifiers are not allowed
   --> testdata/lexer/idents/non-ascii.proto:3:1
-   | 
+   |
  3 | काली बिल्ली
-   | ^^^^ 
+   | ^^^^
 
 error: non-ASCII identifiers are not allowed
   --> testdata/lexer/idents/non-ascii.proto:3:6
-   | 
+   |
  3 | काली बिल्ली
-   |      ^^^^^ 
+   |      ^^^^^
 
 error: non-ASCII identifiers are not allowed
   --> testdata/lexer/idents/non-ascii.proto:4:1
-   | 
+   |
  4 | 黑猫_suffix
-   | ^^^^^^^^^^^ 
+   | ^^^^^^^^^^^
 
 encountered 5 errors

experimental/parser/testdata/lexer/numbers/bad-digit.proto.stderr.txt

@@ -1,31 +1,31 @@
 error: unexpected characters in integer literal
   --> testdata/lexer/numbers/bad-digit.proto:1:1
-   | 
+   |
  1 | 0f
-   | ^^ 
+   | ^^
 
 error: unexpected characters in integer literal
   --> testdata/lexer/numbers/bad-digit.proto:2:1
-   | 
+   |
  2 | 0b02
-   | ^^^^ 
+   | ^^^^
 
 error: unexpected characters in integer literal
   --> testdata/lexer/numbers/bad-digit.proto:3:1
-   | 
+   |
  3 | 0o08
-   | ^^^^ 
+   | ^^^^
 
 error: unexpected characters in integer literal
   --> testdata/lexer/numbers/bad-digit.proto:4:1
-   | 
+   |
  4 | 08
-   | ^^ 
+   | ^^
 
 error: unexpected characters in integer literal
   --> testdata/lexer/numbers/bad-digit.proto:5:1
-   | 
+   |
  5 | 0x0G
-   | ^^^^ 
+   | ^^^^
 
 encountered 5 errors

experimental/parser/testdata/lexer/numbers/exotic-base.proto.stderr.txt

@@ -1,49 +1,49 @@
 error: unsupported base for integer literal
   --> testdata/lexer/numbers/exotic-base.proto:1:1
   help: use a hexadecimal literal instead
-   | 
+   |
  1 | - 0b1100101
  1 | + 0x65
-   | 
+   |
    = note: Protobuf does not support binary literals
 
 error: unsupported base for integer literal
   --> testdata/lexer/numbers/exotic-base.proto:2:1
   help: use a hexadecimal literal instead
-   | 
+   |
  2 | - 0B1010101
  2 | + 0x55
-   | 
+   |
    = note: Protobuf does not support binary literals
 
 error: unsupported base for integer literal
   --> testdata/lexer/numbers/exotic-base.proto:3:1
   help: remove the `o`
-   | 
+   |
  3 | - 0o1234567
  3 | + 01234567
-   | 
+   |
    = note: octal literals are prefixed with `0`, not `0o`
 
 error: unsupported base for integer literal
   --> testdata/lexer/numbers/exotic-base.proto:4:1
   help: remove the `o`
-   | 
+   |
  4 | - 0O1234567
  4 | + 01234567
-   | 
+   |
    = note: octal literals are prefixed with `0`, not `0o`
 
 error: unexpected characters in floating-point literal
   --> testdata/lexer/numbers/exotic-base.proto:6:1
-   | 
+   |
  6 | 0x10203.4
-   | ^^^^^^^^^ 
+   | ^^^^^^^^^
 
 error: unexpected characters in floating-point literal
   --> testdata/lexer/numbers/exotic-base.proto:7:1
-   | 
+   |
  7 | 0X12.ffP10
-   | ^^^^^^^^^^ 
+   | ^^^^^^^^^^
 
 encountered 6 errors

experimental/parser/testdata/lexer/numbers/thousands.proto.stderr.txt

@@ -1,55 +1,55 @@
 error: integer literal contains underscores
   --> testdata/lexer/numbers/thousands.proto:1:1
   help: remove these underscores
-   | 
+   |
  1 | - 1_000_000
  1 | + 1000000
-   | 
+   |
    = note: Protobuf does not support Go/Java/Rust-style thousands separators
 
 error: unsupported base for integer literal
   --> testdata/lexer/numbers/thousands.proto:2:1
   help: use a hexadecimal literal instead
-   | 
+   |
  2 | - 0b1_000_000
  2 | + 0x40
-   | 
+   |
    = note: Protobuf does not support binary literals
 
 error: unsupported base for integer literal
   --> testdata/lexer/numbers/thousands.proto:3:1
   help: remove the `o`
-   | 
+   |
  3 | - 0o1_000_000
  3 | + 01_000_000
-   | 
+   |
    = note: octal literals are prefixed with `0`, not `0o`
 
 error: integer literal contains underscores
   --> testdata/lexer/numbers/thousands.proto:4:1
   help: remove these underscores
-   | 
+   |
  4 | - 0x1_000_000
  4 | + 0x1000000
-   | 
+   |
    = note: Protobuf does not support Go/Java/Rust-style thousands separators
 
 error: integer literal contains underscores
   --> testdata/lexer/numbers/thousands.proto:5:1
   help: remove these underscores
-   | 
+   |
  5 | - 01_000_000
  5 | + 01000000
-   | 
+   |
    = note: Protobuf does not support Go/Java/Rust-style thousands separators
 
 error: floating-point literal contains underscores
   --> testdata/lexer/numbers/thousands.proto:6:1
   help: remove these underscores
-   | 
+   |
  6 | - 1_000_000.00
  6 | + 1000000.00
-   | 
+   |
    = note: Protobuf does not support Go/Java/Rust-style thousands separators
 
 encountered 6 errors

experimental/parser/testdata/lexer/punct.proto.stderr.txt

@@ -1,55 +1,55 @@
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:1
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   | ^ 
+   | ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:3
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |   ^ 
+   |   ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:5
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |     ^ 
+   |     ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:7
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |       ^ 
+   |       ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:9
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |         ^ 
+   |         ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:11
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |           ^ 
+   |           ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:13
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |             ^ 
+   |             ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:15
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |               ^ 
+   |               ^
 
 error: unrecognized token
   --> testdata/lexer/punct.proto:2:17
-   | 
+   |
  2 | ! @ # $ % ^ & * + _
-   |                 ^ 
+   |                 ^
 
 encountered 9 errors

experimental/parser/testdata/lexer/strings/bad-contents.proto.stderr.txt

@@ -1,42 +1,42 @@
 error: unescaped newlines are not permitted in string literals
   --> testdata/lexer/strings/bad-contents.proto:1:13
-   | 
+   |
  1 | "this string
    |             ^ replace this with `\n`
 
 error: unescaped newlines are not permitted in string literals
   --> testdata/lexer/strings/bad-contents.proto:3:2
-   | 
+   |
  3 | "
    |  ^ replace this with `\n`
 
 error: unescaped NUL bytes are not permitted in string literals
   --> testdata/lexer/strings/bad-contents.proto:6:30
-   | 
+   |
  6 | "this string contains a nul: <U+0000>"
    |                              ^^^^^^^^ replace this with `\0` or `\x00`
 
 error: unescaped NUL bytes are not permitted in string literals
   --> testdata/lexer/strings/bad-contents.proto:7:29
-   | 
+   |
  7 | "this string contains a nul <U+0000> in the middle"
    |                             ^^^^^^^^ replace this with `\0` or `\x00`
 
 error: unescaped NUL bytes are not permitted in string literals
   --> testdata/lexer/strings/bad-contents.proto:8:2
-   | 
+   |
  8 | "<U+0000>"
    |  ^^^^^^^^ replace this with `\0` or `\x00`
 
 warning: non-printable character in string literal
   --> testdata/lexer/strings/bad-contents.proto:10:57
-   | 
+   |
 10 | "this string contains some other non-graphic character: <U+0001>"
    |                                                         ^^^^^^^^ help: consider escaping this with e.g. `\x01` instead
 
 warning: non-printable character in string literal
   --> testdata/lexer/strings/bad-contents.proto:11:39
-   | 
+   |
 11 | "this is graphic but non-ASCII space: <U+00A0>"
    |                                       ^^^^^^^^ help: consider escaping this with e.g. `\u00a0` instead