Diff split view paints the whole line for both the new and the old version in a single color

[alvaroaleman]

• Gitea version (or commit ref): 1.0.0
• Can you reproduce the bug at https://try.gitea.io:
  • Yes: https://try.gitea.io/test/gitea/commit/d4924d45d6d4e991240d207a834d8d6709781449?style=split

Description

The split view mode always paints the whole line for both the new and the old version in a single color. This is especially irritating when a line was changed, because then it is completely red which makes it look like that line was removed.

IMHO the view should:

• Display lines that were added white on the left side and green on the right side
• Display lines that were modified red on the left and green on the right side
• Display lines that were removed red on the left and white on the right side

[lunny]

resolved by #584