Add on_exception hook to documentation

[daniellepintz]

The on_exception hook was recently added in #9183 but I forgot to add it to the documentation.
In this PR I also make some very minor fixes.

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[codecov]

Codecov Report

Merging #9365 (2dcadd7) into master (b294c57) will decrease coverage by 4%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #9365    +/-   ##
=======================================
- Coverage      93%     89%    -4%     
=======================================
  Files         180     180            
  Lines       15062   15062            
=======================================
- Hits        13983   13370   -613     
- Misses       1079    1692   +613     

[daniellepintz]

Can I get one more review here please?