Auto merge of rust-lang#131354 - matthiaskrgr:rollup-hprnng2, r=matthiaskrgr

Rollup of 4 pull requests

Successful merges:

 - rust-lang#131331 (Revert "warn_old_master_branch" check)
 - rust-lang#131344 (Avoid `&Lrc<T>` in various places)
 - rust-lang#131346 (Restrict `ignore-mode-*` directives)
 - rust-lang#131353 (Add documentation for `runtest::check_rustdoc_test_option` method)

r? `@ghost`
`@rustbot` modify labels: rollup

Author: bors

clippy_utils/src/source.rs

@@ -287,6 +287,7 @@ impl SourceFileRange {
         self.sf
             .src
             .as_ref()
+            .map(|src| src.as_str())
             .or_else(|| self.sf.external_src.get().and_then(|src| src.get_source()))
             .and_then(|x| x.get(self.range.clone()))
     }