Merge branch '481654-remove-unsed-css-classes-from-hljs' into 'master'

Audit list of classes in app/assets/stylesheets/highlight/hljs.scss

See merge request https://gitlab.com/gitlab-org/gitlab/-/merge_requests/164620



Merged-by: Paul Slaughter <pslaughter@gitlab.com>
Approved-by: Paul Slaughter <pslaughter@gitlab.com>
Co-authored-by: James Rushford <jrushford@gitlab.com>
Co-authored-by: Deepak kumar <kumar.deepak.iiit@gmail.com>

app/assets/stylesheets/highlight/hljs.scss

+/**
+* These hljs css overwrite styling from 'highlight.js/lib/core'
+* Do not remove unless removing the library
+**/
+
 .code.highlight {
   .hljs-comment {
     color: var(--color-hljs-comment);