Namespace header misc change

[nobodyiam]

What's the purpose of this PR

1. show item modified count in lazy init mode so that user could know which namespace to publish
2. show namespace comment as tooltip

Which issue(s) this PR fixes:

Fixes #3082 #3118

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• Read the Contributing Guide before making this pull request.
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[codecov-commenter]

Codecov Report

Merging #3112 into master will not change coverage.
The diff coverage is n/a.

@@            Coverage Diff            @@
##             master    #3112   +/-   ##
=========================================
  Coverage     51.28%   51.28%           
  Complexity     2233     2233           
=========================================
  Files           432      432           
  Lines         13385    13385           
  Branches       1375     1375           
=========================================
  Hits           6864     6864           
  Misses         6048     6048           
  Partials        473      473           

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