- dark
- white
- monokai
- none
- solarized-dark
- solarized-light

Compile highlight CSS separately
Move highlight-specific mixins out of mixins.scss
Rename solarized themes to match theme name as this was a smaller
change than changing all instances to snake_case

Added stylelint to static-analysis
Updated yarn dependencies
CSS Fixes and rule adoptions of stylelint
Added stylelint-scss
Deduplicated yarn.lock to clear dependencies

Fixed scss-lint errors

Previously you just had to hover over a line to see if it could be
commented on, this changes that by changing the background color &
borders to show that the line cant have a comment.

Fixed hll overriding is-over class

It now shows the line will be commenting on my highlight the line number cells with a lighter color. The button has also been made smaller, it was previously way over the top & took over a lot more space than it should of done

Closes #27543

Added highlight colours to diff rows

Closes #13852

Use lowercase letters and shorthand values for HEX colors where
possible.

Discussed in #14299.

Now we don't need to override the user color scheme on search results.
They'll look good with any of them.

Also preserve code preview color scheme in events dashboard.

Assign default colors to all code blocks shown as <pre class="code highlight [color_scheme]">

Closes #1139

I decided to create a fork of rouge as rouge lacks a HTML formatter with
the required options such as wrapping a line with <span> tags.
Furthermore I was not really convinced about the clarity of rouge's
source code.

Rugments 1.0.0beta3 for now only includes some basic linting and a new
HTML formatter. Everything else should behave the same.

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

This unifies the code color-scheme code and makes
adding new schemes a little easier.