Ensure that hidden event is sent when content is really hidden (collapsing class is removed)
Revert "Use mousedown instead of click for backdrop click detection; fixes #13816"
Remove `aria-describedby` attribute later

Fixes #14241
Collapse: count `.collapsing` elements as actives; closes #13447
Fixes #14348: Add visibility styles to collapse and tab content to match .hidden
Update print.less from source (html5-boilerplate). Simplyfy table style.
Less: Remove empty lines and blanks.
Specify `cursor: pointer` for `#import-manual-trigger`.
Update dev dependencies.
Update Ruby dependencies.
Merge pull request #14458 from twbs/npm-deps

Update dev dependencies.
Merge pull request #14453 from vsn4ik/less_empty_lines

Less: Remove empty lines and blanks.
Make `popover-arrow-color` default to `popover-bg`
fix nav links to end with / to avoid 301 redirect
grunt
Merge pull request #14465 from kaime/master

Make `popover-arrow-color` default to `popover-bg`
Merge pull request #14452 from vsn4ik/update_print_less

Update print.less from source (html5-boilerplate).
grunt
Merge branch 'master' into sr_friendly_hidden_content

Conflicts:
	dist/css/bootstrap.css.map
	dist/css/bootstrap.min.css
typo