Move diff split code into own template file

[mrsdizzie]

Separate split diff view same as unified already is. Mainly because I'm working on a separate PR with this change and merge conflicts for each change to box.tmpl are annoying and I'm worried about breaking something subtle while trying to resolve them.

[codecov-io]

Codecov Report

Merging #13919 (cfbee9c) into master (c85bb62) will increase coverage by 0.10%.
The diff coverage is n/a.

@@            Coverage Diff             @@
##           master   #13919      +/-   ##
==========================================
+ Coverage   42.11%   42.22%   +0.10%     
==========================================
  Files         710      710              
  Lines       77227    77227              
==========================================
+ Hits        32527    32610      +83     
+ Misses      39350    39252      -98     
- Partials     5350     5365      +15     

Impacted Files	Coverage Δ
models/repo_mirror.go	2.38% <0.00%> (-11.91%)	⬇️
modules/cron/tasks_basic.go	87.35% <0.00%> (-3.45%)	⬇️
services/mirror/mirror.go	15.78% <0.00%> (-1.11%)	⬇️
modules/git/repo.go	45.72% <0.00%> (-1.01%)	⬇️
models/gpg_key.go	53.33% <0.00%> (-0.58%)	⬇️
models/error.go	39.31% <0.00%> (+0.32%)	⬆️
services/pull/pull.go	40.68% <0.00%> (+0.49%)	⬆️
services/pull/check.go	51.82% <0.00%> (+0.72%)	⬆️
models/notification.go	67.24% <0.00%> (+0.98%)	⬆️
services/gitdiff/gitdiff.go	70.98% <0.00%> (+1.93%)	⬆️
... and 8 more

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update c85bb62...cfbee9c. Read the comment docs.

[silverwind]

Getting this error:

template: repo/diff/comments:3:45: executing "repo/diff/comments" at <$.root.Lang>: invalid value; expected string

[mrsdizzie]

Getting this error:

template: repo/diff/comments:3:45: executing "repo/diff/comments" at <$.root.Lang>: invalid value; expected string

Thats what I'm talking about : ) Fixed thanks!

[techknowlogick]

🚀