Relax sanitization as per https://github.com/jch/html-pipeline

[zeripath]

Looking at github/markup#245 it is clear that GH uses https://github.com/jch/html-pipeline to sanitize. This PR relaxes our sanitization to more closely match this.

Fixes #10471
and likely others...

[codecov-io]

Codecov Report

Merging #10527 into master will increase coverage by 0.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master   #10527      +/-   ##
==========================================
+ Coverage   43.69%    43.7%   +0.01%     
==========================================
  Files         586      586              
  Lines       81521    81553      +32     
==========================================
+ Hits        35617    35642      +25     
- Misses      41491    41495       +4     
- Partials     4413     4416       +3

Impacted Files	Coverage Δ
modules/markup/sanitizer.go	92.2% <100%> (+5.54%)	⬆️
modules/indexer/stats/queue.go	62.5% <0%> (-18.75%)	⬇️
modules/indexer/stats/db.go	40.62% <0%> (-9.38%)	⬇️
modules/git/utils.go	65.67% <0%> (-4.48%)	⬇️
modules/log/file.go	75.52% <0%> (-2.1%)	⬇️
services/pull/pull.go	34.89% <0%> (-1.18%)	⬇️
modules/queue/workerpool.go	56.93% <0%> (-1.07%)	⬇️
modules/git/repo.go	46.78% <0%> (-0.92%)	⬇️
services/pull/check.go	52.43% <0%> (+2.43%)	⬆️
services/pull/patch.go	62.89% <0%> (+2.51%)	⬆️
... and 2 more

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[alexanderadam]

You are awesome, @zeripath! 🙏

[zeripath]

make lg-tm work