[#2568] Add linter for known issues id.

Problem
========

When we fix a known issues and we forget to remove it from know issues 

Changes
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Add a regex rule for ticket id similar to the way we put them in known issues `[#1234]`.
I kept the regex for all files as in the future we might want to add ticket id in other documentation pages.


How to test
=========

reviewers: @alibotean 


this is just to let you know about the changes.
one released I will integrate it in the next server merge.

you can test by installing 0.48.0 on a server branch and manually changing the known issues to refer to an ticket id similar to this branch id.

Thanks!