Rollup merge of rust-lang#78962 - poliorcetics:rustdoc-raw-ident-test…

…, r=jyn514

Add a test for r# identifiers

I'm not entirely sure I properly ran the test locally (I think so though), waiting for CI to confirm. :)

```@rustbot``` modify labels: T-rustdoc

r? ```@jyn514```

src/test/rustdoc/raw-ident-eliminate-r-hashtag.rs

@@ -0,0 +1,22 @@
+// ignore-tidy-linelength
+
+#![crate_type="lib"]
+
+pub mod internal {
+    // @has 'raw_ident_eliminate_r_hashtag/internal/struct.mod.html'
+    pub struct r#mod;
+
+    /// See [name], [other name]
+    ///
+    /// [name]: mod
+    /// [other name]: crate::internal::mod
+    // @has 'raw_ident_eliminate_r_hashtag/internal/struct.B.html' '//*a[@href="../../raw_ident_eliminate_r_hashtag/internal/struct.mod.html"]' 'name'
+    // @has 'raw_ident_eliminate_r_hashtag/internal/struct.B.html' '//*a[@href="../../raw_ident_eliminate_r_hashtag/internal/struct.mod.html"]' 'other name'
+    pub struct B;
+}
+
+/// See [name].
+///
+/// [name]: internal::mod
+// @has 'raw_ident_eliminate_r_hashtag/struct.A.html' '//*a[@href="../raw_ident_eliminate_r_hashtag/internal/struct.mod.html"]' 'name'
+pub struct A;