fix code block markers

Author: tshepang

src/rustdoc-internals.md

@@ -283,7 +283,7 @@ Some features of the generated `HTML` documentation might require local
 storage to be used across pages, which doesn't work well without an `HTTP` server.
 To test these features locally, you can run a local `HTTP` server, like this:
 
-```bash
+```console
 $ ./x doc library
 # The documentation has been generated into `build/[YOUR ARCH]/doc`.
 $ python3 -m http.server -d build/[YOUR ARCH]/doc

src/rustdoc.md

@@ -65,7 +65,7 @@ Note that literally all that does is call the `main()` that's in this crate's `l
 Rustdoc’s JavaScript and TypeScript are checked during CI by `eslint`, `es-check`, and `tsc` (not by compiletest).
 These run as part of the `tidy` job.
 
-```bash
+```console
 ./x.py test tidy --extra-checks=js
 ```