[doc] Add linked references for message in old whatsnews

[Pierre-Sassoulas]

Type of Changes

	Type
✓	📜 Docs

Description

Manually taken from #10568 which still has some issues with detecting code inside doc. There's probably 404 in here as long as we don't implement #6670

[Pierre-Sassoulas]

Well there's a lot more work than I thought :

We also need to cleanup the msgid if it exists.

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.
✅ Project coverage is 95.96%. Comparing base (77c63d6) to head (2bde6f5).
⚠️ Report is 1 commits behind head on main.

Additional details and impacted files

@@           Coverage Diff           @@
##             main   #10638   +/-   ##
=======================================
  Coverage   95.96%   95.96%           
=======================================
  Files         176      176           
  Lines       19502    19502           
=======================================
  Hits        18715    18715           
  Misses        787      787           

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[Pierre-Sassoulas]

There's a lot of old messages that were not detected because they are not in the message store anymore, so maybe no 404 contrary to what I said in the description.

[Pierre-Sassoulas]

Last MR before #10639 😄