Pin sphinx <7.2

[sondreso]

Issue
An excpetion occours when using sphinx version 7.2.0. Possible incompatability with Furo theme.

Created issue #5893

Approach
Pin and create issue to unpin

Pre review checklist

• Added appropriate release note label
• PR title captures the intent of the changes, and is fitting for release notes.
• Commit history is consistent and clean, in line with the contribution guidelines.
• Updated documentation
• Ensured new behaviour is tested

Adding labels helps the maintainers when writing release notes. This is the list of release note labels.

[codecov-commenter]

Codecov Report

Merging #5892 (8f4df30) into main (a07afe4) will increase coverage by 0.11%.
Report is 21 commits behind head on main.
The diff coverage is n/a.

@@            Coverage Diff             @@
##             main    #5892      +/-   ##
==========================================
+ Coverage   81.77%   81.89%   +0.11%     
==========================================
  Files         347      347              
  Lines       21616    21613       -3     
  Branches      737      737              
==========================================
+ Hits        17677    17699      +22     
+ Misses       3686     3661      -25     
  Partials      253      253              

see 24 files with indirect coverage changes

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[valentin-krasontovitsch]

great, thank you!