[TASK] Polish the "git commits" section of CONTRIBUTING.md (#1380)

Part of #1360

CONTRIBUTING.md

@@ -111,14 +111,14 @@ composer fix
 
 ## Git commits
 
-Commit message should have a <= 50 character summary, optionally followed by a
+Commit message should have a <= 50-character summary, optionally followed by a
 blank line and a more in depth description of 79 characters per line.
 
 Please use grammatically correct, complete sentences in the commit messages.
 
 Also, please prefix the subject line of the commit message with either
-[FEATURE], [TASK], [BUGFIX] OR [CLEANUP]. This makes it faster to see what
-a commit is about.
+`[FEATURE]`, `[TASK]`, `[BUGFIX]` OR `[CLEANUP]`. This makes it faster to see
+what a commit is about.
 
 ## Creating pull requests (PRs)