Docs: progress bars' animation now needs to be manually toggled

Refs #14409
bs-commonjs-generator.js: always use forward slashes in the require path.

Since `path.resolve` is using backslashes on Windows, we ended up with different files. Just replace those with forward slashes.
Docs: progress bars' animation now needs to be manually toggled

Refs #14409
Merge pull request #14876 from twbs/fix-14875

bs-commonjs-generator.js: always use forward slashes in the require path.
Merge branch 'need-to-activate-animated-progressbar' of github.com:twbs/bootstrap into need-to-activate-animated-progressbar

Conflicts:
	docs/_includes/components/progress-bars.html
	docs/assets/js/src/application.js
grunt
Merge branch 'master' into need-to-activate-animated-progressbar