Add button to revert SimpleMDE to plain textarea

[zeripath]

This will allow android users to switch off the SimpleMDE editor in the review approve/comment/request changes area.

[codecov-io]

Codecov Report

Merging #10099 into master will decrease coverage by <.01%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #10099      +/-   ##
==========================================
- Coverage   43.44%   43.44%   -0.01%     
==========================================
  Files         566      566              
  Lines       78989    78989              
==========================================
- Hits        34320    34316       -4     
  Misses      40432    40432              
- Partials     4237     4241       +4

Impacted Files	Coverage Δ
services/pull/patch.go	64.77% <0%> (-3.15%)	⬇️
modules/queue/workerpool.go	46.61% <0%> (-1.78%)	⬇️
services/pull/merge.go	51.36% <0%> (-0.69%)	⬇️
services/pull/pull.go	33.93% <0%> (-0.31%)	⬇️
models/repo.go	51.46% <0%> (+0.13%)	⬆️
services/pull/check.go	56.64% <0%> (+2.09%)	⬆️
models/unit.go	39.5% <0%> (+2.46%)	⬆️
services/pull/temp_repo.go	34.18% <0%> (+2.56%)	⬆️

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[jolheiser]

It might be nice to be able to turn it back into an MDE, but other than that LGTM. Can I approve this twice? 😂

[lafriks]

Would be nice if it would not initialize simplemde if opened from mobile phone with option to enable it manually

[jolheiser]

Since this is technically a bug (not being able to easily review on mobile) can it be backported to 1.11? 😁

[zeripath]

make lg-tm work