- Simpler main nav on all pages
- Back to purple masthead on homepage instead of dark graphite
- Active link styles on the main nav
- Cleaned up sidebar nav
- New docs layout name
- Homepage copy edits
- Updated bright purple docs color

(also fix license banner generator bug)

X-Ref #16583

[ci skip]

Add a license header in theme instead.

Anchor.js 1.0.0 drops the need to use anchor.css, so we remove it
from the codebase and move any leftover styles over to docs.css.

Closes #16488 by merging it.

add modal my gawd

[skip sauce]
[skip validator]

Make it so that everything is done for us to reduce the possibility of missing something when releasing.

Only used for the GitHub docs.

Refs https://github.com/twbs/bootstrap/issues/14837#issuecomment-77441999

This allows `grunt jscs:grunt` to succeed.