Add specific code review guidelines

doc/development/code_review.md

@@ -9,8 +9,16 @@ There are a few rules to get your merge request accepted:
     **approved by a [backend maintainer][projects]**.
   1. If your merge request includes only frontend changes [^1], it must be
     **approved by a [frontend maintainer][projects]**.
+  1. If your merge request includes UX changes [^1], it must
+    be **approved by a [UX team member][team]**.
+  1. If your merge request includes adding a new JavaScript library [^1], it must be
+    **approved by a [frontend lead][team]**.
   1. If your merge request includes frontend and backend changes [^1], it must
     be **approved by a [frontend and a backend maintainer][projects]**.
+  1. If your merge request includes UX and frontend changes [^1], it must
+    be **approved by a [UX team member and a frontend maintainer][team]**.
+  1. If your merge request includes UX, frontend and backend changes [^1], it must
+    be **approved by a [UX team member, a frontend and a backend maintainer][team]**.
 1. To lower the amount of merge requests maintainers need to review, you can
   ask or assign any [reviewers][projects] for a first review.
   1. If you need some guidance (e.g. it's your first merge request), feel free