Add missing labels to changelog sections ...

[jlaehne]

Description of the change

Add missing labels du changelog, metadata sections; correct in install.rst
(needed for cross-references from LumiSpy)

Progress of the PR

• Change implemented (can be split into several points),
• update user guide (if appropriate),
• ready for review.

[codecov]

Codecov Report

Base: 80.60% // Head: 80.60% // No change to project coverage 👍

Coverage data is based on head (0883183) compared to base (b47d0ea).
Patch has no changes to coverable lines.

Additional details and impacted files

@@                 Coverage Diff                 @@
##           RELEASE_next_major    #3086   +/-   ##
===================================================
  Coverage               80.60%   80.60%           
===================================================
  Files                     176      176           
  Lines                   24476    24476           
  Branches                 5383     5383           
===================================================
  Hits                    19729    19729           
  Misses                   3421     3421           
  Partials                 1326     1326           

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

☔ View full report at Codecov.
📢 Do you have feedback about the report comment? Let us know in this issue.