Add some padding to the shadowed comment box

[zeripath]

Add a small amount of padding (4px) to the highlighted comment box - thus preventing the shadow from looking to crowded.

Previously:

Now:

[codecov-io]

Codecov Report

Merging #9612 into master will decrease coverage by <.01%.
The diff coverage is 100%.

@@            Coverage Diff             @@
##           master    #9612      +/-   ##
==========================================
- Coverage   42.17%   42.17%   -0.01%     
==========================================
  Files         578      578              
  Lines       76066    76070       +4     
==========================================
  Hits        32083    32083              
- Misses      40004    40008       +4     
  Partials     3979     3979

Impacted Files	Coverage Δ
models/repo_list.go	74.42% <100%> (+0.35%)	⬆️
routers/home.go	46.87% <100%> (+0.18%)	⬆️
modules/process/manager.go	74.69% <0%> (-3.62%)	⬇️
routers/repo/view.go	38.59% <0%> (-0.88%)	⬇️
models/gpg_key.go	55.59% <0%> (+0.55%)	⬆️

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