Update documentation about changelog entries for trivial changes

[jugmac00]

This fixes #2007

Part of the #2007 was already fixed by #2006, ie the paragraph about how
to create pseudo towncrier snippets was removed.

• wrote descriptive pull request text
• added/updated test(s)
• updated/extended the documentation
• added relevant issue keyword
  in message body
• added news fragment in changelog folder

[codecov]

Codecov Report

Merging #2010 (c489d58) into rewrite (1a50180) will increase coverage by 0.16%.
The diff coverage is n/a.

@@             Coverage Diff              @@
##           rewrite     #2010      +/-   ##
============================================
+ Coverage    99.83%   100.00%   +0.16%     
============================================
  Files          147       145       -2     
  Lines         8286      8123     -163     
  Branches       825       797      -28     
============================================
- Hits          8272      8123     -149     
+ Misses           3         0       -3     
+ Partials        11         0      -11     

Flag	Coverage Δ
tests	100.00% <ø> (+0.16%)	⬆️

Flags with carried forward coverage won't be shown. Click here to find out more.

Impacted Files	Coverage Δ
src/tox/tox_env/api.py	100.00% <0.00%> (ø)
src/tox/execute/request.py	100.00% <0.00%> (ø)
src/tox/util/pep517/backend.py	100.00% <0.00%> (ø)
...ecute/local_sub_process/read_via_thread_windows.py
tests/conftest.py
src/tox/tox_env/python/api.py	100.00% <0.00%> (+0.77%)	⬆️
src/tox/config/loader/str_convert.py	100.00% <0.00%> (+1.56%)	⬆️
src/tox/util/spinner.py	100.00% <0.00%> (+2.27%)	⬆️
src/tox/execute/local_sub_process/__init__.py	100.00% <0.00%> (+4.32%)	⬆️

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