Update src/implementing_new_feature.md

Co-Authored-By: rajcspsg <[email protected]>

Author: mark-i-m

src/implementing_new_feature.md

@@ -78,7 +78,7 @@ For other features, you'll have to make a tracking issue for that feature. The i
 
 For tracking issues for features (as opposed to future-compat warnings), I don't think the description has to contain anything specific. Generally we put the list of items required for stabilization using a github list, e.g.
 
-```bash, ignore
+```txt
     **Steps:**
 
     - [ ] Implement the RFC (cc @rust-lang/compiler -- can anyone write up mentoring instructions?)
@@ -132,4 +132,4 @@ https://github.com/rust-lang/rust-forge/blob/master/rustc-bug-fix-procedure.md
 [value the stability of Rust]: https://github.com/rust-lang/rfcs/blob/master/text/1122-language-semver.md
 [stability in code]:
 [here]: https://rust-lang.github.io/rustc-guide/stabilization_guide.html
-[tracking issue]: 
+[tracking issue]: