* Alternative fix for HTML diff entity split
This commit both reverts PR #13357 and uses the exiting implementation alredy used for spans to fix the same issue. That PR duplicates most of logic that is already present elsewhere and still was failing for some cases. This should be simpler as it uses the existing logic that already works for <span>s being split apart.
Added both test cases as well.
* Update gitdiff_test.go
* fmt
* entity can have uppercase letter, also add detailed comment per @zeripath
d7e0983780