Update linker-plugin-lto.md

Author: nico-abram

Diff for: src/doc/rustc/src/linker-plugin-lto.md

@@ -104,7 +104,7 @@ clang-cl --version
 
 If you are compiling any proc-macros, you will get this error:
 
-```
+```bash
 error: Linker plugin based LTO is not supported together with `-C prefer-dynamic` when
 targeting Windows-like targets
 ```