Add option to ignore whitespace in diffs

[tobias--]

• Gitea version (or commit ref): 1.1.2

Description

It would be great to have the ability to ignore whitespace in diffs on demand. For example, Github allows you to do this by adding '?w=1' to the URL. See https://github.com/blog/967-github-secrets

[tonivj5]

woow, that trick is awesome! Thanks 😄

[tobias--]

I just noticed: This issue duplicates #716.

[andreynering]

@tobias-- In this case let's close this in favor of #716