Inconsistent code style in HTML, JavaScript, and CSS files

[Trey Hunner]

There are multiple inconsistent code styles used throughout the Django project.

It appears that the overall preferred style for HTML is 2 spaces, JavaScript is 2 or 4 spaces (and sometimes tabs) and CSS is 4 spaces.

It seems that all files should have newlines at the end and whitespace should be trimmed from the end of each line.

I am currently working on discovering the existing code style, fixing obvious unintended inconsistencies, and creating a .editorconfig file to document the expectations for future code changes.

[Trey Hunner]

I started a pull request for this ticket here: ​https://github.com/django/django/pull/2577

[Trey Hunner]

I added a (nearly empty) .jshintrc file to the pull request. The preferred code style should be decided (I prefer the default JSHint style) and the existing code should be modified to adhere to the style.

[Russell Keith-Magee]

Accepted on the principle that we Flake8 our Python code; linting our JavaScript would also seem prudent. The only decision is the choice of linter. ​See this django-dev thread for discussion.

[Tomek Paczkowski]

Looks like there is new PR for this: ​https://github.com/django/django/pull/4577

[Tim Graham <timograham@…>]

In ec4f219:

Fixed #22463 -- Added code style guide and JavaScript linting (EditorConfig and ESLint)

[GitHub <noreply@…>]

In 7b4bd2a8:

Refs #22463 -- Replaced JSHint with ESLint in contributing docs.

[Mariusz Felisiak <felisiak.mariusz@…>]

In abe33c16:

[3.0.x] Refs #22463 -- Replaced JSHint with ESLint in contributing docs.

Backport of 7b4bd2a82c4709a9078fed5c33fa94f208a8c41e from master