Collapse: count `.collapsing` elements as actives; closes #13447
Scrollspy: ignore invisible list items

Fixes #13071
add role="tab" to .panel-heading-s in accordion example to improve accessibility
Merge pull request #14579 from twbs/accordion-heading-role-tab

add role="tab" to .panel-heading-s in accordion example to improve accessibility
Merge pull request #14353 from hnrch02/collapse-count-collapsing-as-active

Collapse: count `.collapsing` elements as actives; closes #13447
Merge pull request #14569 from twbs/scrollspy-ignore-invisible-targets

Scrollspy: ignore invisible list items
add aria-labelledby to accordion example to improve accessibility
grunt
Merge pull request #14578 from twbs/accordion-panel-labelledby

add aria-labelledby to accordion example to improve accessibility
Properly fire hidden event when tooltip is destroyed

Fixes #13031.
Merge pull request #14571 from twbs/properly-hide-tooltip-on-destroy

Properly fire hidden event when tooltip is destroyed
Teh grunt

https://www.youtube.com/watch?v=L-4VxEtWyRo
Correctly selects arrow placement for a tooltip

Fixes #13696.
Fixes #13696.
Fixes #14197.
Closes #13718.
grunt
Update github links in footer.
Merge pull request #14612 from vsn4ik/update_docs_links

Update github links in footer.