x/pkgsite: fails to escape backtick-quotes in doc comments

[bcmills]

What is the URL of the page with the issue?

https://pkg.go.dev/reflect#DeepEqual

What is your user agent?

Mozilla/5.0 (X11; CrOS x86_64 13421.89.0) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/86.0.4240.183 Safari/537.36

Screenshot

What did you do?

Open documentation for reflect.DeepEqual.

What did you expect to see?

The same text as produced by go doc reflect.DeepEqual, with the idiosyncratic backtick-quotes replaced with proper Unicode quotes (per #27759, #41958, and others):

~$ gotip version
go version devel +869e2957b Mon Nov 16 22:24:14 2020 +0000 linux/amd64

~$ gotip doc reflect.DeepEqual | head -n 6
package reflect // import "reflect"

func DeepEqual(x, y interface{}) bool
    DeepEqual reports whether x and y are “deeply equal,” defined as follows.
    Two values of identical type are deeply equal if one of the following cases
    applies. Values of distinct types are never deeply equal.

What did you see instead?

Unescaped backticks and quote characters from the original source code:

go/src/reflect/deepequal.go

Lines 160 to 162 in c53315d

	// DeepEqual reports whether x and y are ``deeply equal,'' defined as follows.
	// Two values of identical type are deeply equal if one of the following cases applies.
	// Values of distinct types are never deeply equal.

[gopherbot]

Change https://golang.org/cl/274251 mentions this issue: internal/godoc/dochtml/internal/render: support unicode quotes