Enforce tab indentation in templates

[silverwind]

This adds editorconfig-checker [1] to lint the template files so they conform the editorconfig files. I fixed all current identation issues using the fix mode of eclint [2] and some manual corrections.

We can extend this linting to other files later, for now I'd like this PR to focus on HTML template files only.

[1] https://github.com/editorconfig-checker/editorconfig-checker
[2] https://github.com/jedmao/eclint

[silverwind]

Note, the checker module is actually https://github.com/editorconfig-checker/editorconfig-checker.javascript which is a JS wrapper around the golang tool, for ease of installation using npm.

[silverwind]

Rebased

Diff is best viewed with whitespace disabled: https://github.com/go-gitea/gitea/pull/15289/files?diff=unified&w=1

[6543]

I'd like to have this for sooo long :D - thanks

[6543]

@silverwind one thing missing:

templates/repo/issue/milestones.tmpl:
        17: Wrong indentation type(spaces instead of tabs)

[silverwind]

And it swiftly caught a rebase error of mine, fixed.

https://drone.gitea.io/go-gitea/gitea/38396/1/3

[6543]

this hopefully let us prevent issues like: #14719, ...

[silverwind]

It does only lint the intendation, imbalanced tags are still possible and I'm looking for a linter that can detect these. Maybe https://github.com/ember-template-lint/ember-template-lint.

[6543]

@silverwind what command did you use for auto-fix the templates, I'll need this to resolve conflicts in other pulls :)

[silverwind]

npm i -g eclint
eclint fix <file>

Be aware it does not fix all cases. Also see https://github.com/jedmao/eclint#cli