Rollup merge of rust-lang#79321 - camelid:intra-doc-bang, r=Manishearth

Accept '!' in intra-doc links

This will allow linking to things like `Result<T, !>`.

*See <https://github.com/rust-lang/rust/pull/77832#discussion_r528409079>.*

r? `@jyn514`

Author: Dylan-DPC

src/librustdoc/passes/collect_intra_doc_links.rs

@@ -1022,7 +1022,7 @@ impl LinkCollector<'_, '_> {
             (link.trim(), None)
         };
 
-        if path_str.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, ".contains(ch))) {
+        if path_str.contains(|ch: char| !(ch.is_alphanumeric() || ":_<>, !".contains(ch))) {
             return None;
         }
 

src/test/rustdoc/intra-doc-link-generic-params.rs

@@ -15,8 +15,11 @@
 // @has foo/index.html '//a[@href="https://doc.rust-lang.org/nightly/core/option/enum.Option.html"]' 'with the generic, Option<T>'
 
 //! We should also try linking to [`Result<T, E>`]; it has *two* generics!
+//! And [`Result<T, !>`] and [`Result<!, E>`].
 //!
 // @has foo/index.html '//a[@href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html"]' 'Result<T, E>'
+// @has foo/index.html '//a[@href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html"]' 'Result<T, !>'
+// @has foo/index.html '//a[@href="https://doc.rust-lang.org/nightly/core/result/enum.Result.html"]' 'Result<!, E>'
 
 //! Now let's test a trickier case: [`Vec::<T>::new`], or you could write it
 //! [with parentheses as `Vec::<T>::new()`][Vec::<T>::new()].