Merge branch 'labels-grammar' into 'master'

Fix same tiny grammar mistake as in ee

This is a tiny grammar fix that was already merged into EE

https://gitlab.com/gitlab-org/gitlab-ee/merge_requests/667#note_14043471

See merge request !5865

doc/user/project/labels.md

 # Labels
 
 Labels provide an easy way to categorize the issues or merge requests based on
-descriptive titles like `bug`, `documentation` or any other text you feel like
-it. They can have different colors, a description, and are visible throughout
+descriptive titles like `bug`, `documentation` or any other text you feel like.
+They can have different colors, a description, and are visible throughout
 the issue tracker or inside each issue individually.
 
 With labels, you can navigate the issue tracker and filter any bloated