fix(remove): On error, suggest other dependencies (rust-lang#14818)

### What does this PR try to resolve?

`cargo remove` already will suggest other tables if appropriate.
`cargo add` auto-corrects `_` and `-`.

This is an extension of the two by suggesting existing dependencies
within the same table that are "close".

Related to rust-lang#14814

### How should we test and review this PR?

I chose to make alt tables and alt deps mutually exclusive in the
message because I didn't wantto deal with how to separate things if both
show up.
Most likely, people will only expect one or the other and if its in an
alt table, then most likely they mean that.

### Additional information

src/cargo/util/toml_mut/manifest.rs

@@ -9,6 +9,7 @@ use anyhow::Context as _;
 use super::dependency::Dependency;
 use crate::core::dependency::DepKind;
 use crate::core::{FeatureValue, Features, Workspace};
+use crate::util::closest;
 use crate::util::interning::InternedString;
 use crate::{CargoResult, GlobalContext};
 
@@ -381,6 +382,13 @@ impl LocalManifest {
                 }
             }
             None => {
+                let names = parent_table
+                    .as_table_like()
+                    .map(|t| t.iter())
+                    .into_iter()
+                    .flatten();
+                let alt_name = closest(name, names.map(|(k, _)| k), |k| k).map(|n| n.to_owned());
+
                 // Search in other tables.
                 let sections = self.get_sections();
                 let found_table_path = sections.iter().find_map(|(t, i)| {
@@ -393,6 +401,7 @@ impl LocalManifest {
                     name,
                     table_path.join("."),
                     found_table_path,
+                    alt_name.as_deref(),
                 ));
             }
         }
@@ -605,10 +614,13 @@ fn non_existent_dependency_err(
     name: impl std::fmt::Display,
     search_table: impl std::fmt::Display,
     found_table: Option<impl std::fmt::Display>,
+    alt_name: Option<&str>,
 ) -> anyhow::Error {
     let mut msg = format!("the dependency `{name}` could not be found in `{search_table}`");
     if let Some(found_table) = found_table {
         msg.push_str(&format!("; it is present in `{found_table}`",));
+    } else if let Some(alt_name) = alt_name {
+        msg.push_str(&format!("; dependency `{alt_name}` exists",));
     }
     anyhow::format_err!(msg)
 }

tests/testsuite/cargo_remove/invalid_dep/in/Cargo.toml

@@ -0,0 +1,22 @@
+[package]
+name = "cargo-remove-test-fixture"
+version = "0.1.0"
+edition = "2015"
+
+[[bin]]
+name = "main"
+path = "src/main.rs"
+
+[build-dependencies]
+semver = "0.1.0"
+
+[dependencies]
+invalid-dependency-name = "0.6"
+docopt = "0.6"
+semver = "0.1"
+
+[dev-dependencies]
+serde = "1.0.90"
+
+[features]
+std = ["serde/std", "semver/std"]

tests/testsuite/cargo_remove/invalid_dep/in/src/lib.rs

@@ -0,0 +1 @@
+

tests/testsuite/cargo_remove/invalid_dep/mod.rs

@@ -9,11 +9,9 @@ use cargo_test_support::Project;
 #[cargo_test]
 fn case() {
     cargo_test_support::registry::init();
-    cargo_test_support::registry::Package::new("clippy", "0.4.0+my-package").publish();
+    cargo_test_support::registry::Package::new("invalid-dependency-name", "0.6.2+my-package")
+        .publish();
     cargo_test_support::registry::Package::new("docopt", "0.6.2+my-package").publish();
-    cargo_test_support::registry::Package::new("regex", "0.1.1+my-package").publish();
-    cargo_test_support::registry::Package::new("rustc-serialize", "0.4.0+my-package").publish();
-    cargo_test_support::registry::Package::new("toml", "0.1.1+my-package").publish();
     cargo_test_support::registry::Package::new("semver", "0.1.1")
         .feature("std", &[])
         .publish();

tests/testsuite/cargo_remove/invalid_dep/out/Cargo.toml

@@ -11,14 +11,11 @@ path = "src/main.rs"
 semver = "0.1.0"
 
 [dependencies]
+invalid-dependency-name = "0.6"
 docopt = "0.6"
-rustc-serialize = "0.4"
 semver = "0.1"
-toml = "0.1"
-clippy = "0.4"
 
 [dev-dependencies]
-regex = "0.1.1"
 serde = "1.0.90"
 
 [features]