Enable Style/IndentAssignment Rubocop style cop

Checks the indentation of the first line of the right-hand-side of a multi-line assignment.

See #17478

See merge request !4348

Enable Style/WhileUntilDo rubocop style cop

Checks for redundant `do` after `while` or `until`.

See #17478

See merge request !4350

Enable Style/EndOfLine Rubocop style cop

Use Unix-style line endings.

Removed carriage return character from end of each line in `app/controllers/projects/find_file_controller.rb`

See #17478

See merge request !4347

Enable Lint/BlockAlignment Rubocop cop

See #17478

See merge request !4346

Enable Style/RedundantParentheses rubocop cop

Checks for parentheses that seem not to serve any purpose.

See #17478 

See merge request !4361

Enable Style/SpaceBeforeComment rubocop cop

See #17478 

See merge request !4358

Enable Style/SpaceAfterMethodName rubocop cop

Do not put a space between a method name and the opening parenthesis  in a method definition.

See #17478

See merge request !4359

See #17478

See #17478

See #17478

See #17478

Add DB index on users.state

See merge request !4336

See #17478

Use Unix-style line endings. See #17478.

See #17478

Closes #17920

Improve note validation

This MR improves note validation. Originates from #15577.

Closes #17260

See merge request !4024

❤

Use absolute paths in .gitignore

See merge request !4335

It's working fine now but by making it more explicit we can make tools
like 'The Silver Searcher' to parse properly the .gitignore file

Closes https://gitlab.com/gitlab-org/gitlab-ce/issues/15577

Use $ as the snippet prefix so it's consistent

## What does this MR do?

Change like `Snippet #20073` to `Snippet $20073`

## Are there points in the code the reviewer needs to double check?

Are there any other places need this change?

See merge request !4338

Project#show on projects pending deletion will 404

fixes #17508

See merge request !4156

fixes #17508