Fix docs for auto_lr_find

[edenlightning]

What does this PR do?

Fixes # (issue)

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[codecov]

Codecov Report

Merging #3883 into master will increase coverage by 3%.
The diff coverage is n/a.

@@           Coverage Diff           @@
##           master   #3883    +/-   ##
=======================================
+ Coverage      84%     87%    +3%     
=======================================
  Files         119     117     -2     
  Lines        9764    9262   -502     
=======================================
- Hits         8169    8028   -141     
+ Misses       1595    1234   -361