Add docs for issue activity sort feature

doc/user/project/issues/managing_issues.md

@@ -7,7 +7,7 @@ you can do with issues.
 
 ## Create a new Issue
 
-When you create a new issue, you'll be prompted to fill in the [data and fields of the issue](issue_data_and_actions.md#parts-of-an-issue), as illustrated below. If you know
+When you create a new issue, you'll be prompted to fill in the [data and fields of the issue](issue_data_and_actions.md), as illustrated below. If you know
 the values you want to assign to an issue, you can use the [Quick actions](../quick_actions.md)
 feature to input values, instead of selecting them from lists.
 

doc/user/project/issues/multiple_assignees_for_issues.md

 # Multiple Assignees for Issues **(STARTER)**
 
-> **Note:**
-[Introduced](https://gitlab.com/gitlab-org/gitlab/issues/1904)
-in [GitLab Starter 9.2](https://about.gitlab.com/releases/2017/05/22/gitlab-9-2-released/#multiple-assignees-for-issues).
+> [Introduced](https://gitlab.com/gitlab-org/gitlab/issues/1904) in [GitLab Starter 9.2](https://about.gitlab.com/releases/2017/05/22/gitlab-9-2-released/#multiple-assignees-for-issues).
 
 ## Overview