* use a mixin there
* revamp .btn-link to match default and outline variants
* remove unnecessary properties

move max-width: 100% on .container to the root of the make-container mixin so it's not repeated at compilation (#22947)

Update Jekyll to v3.5.2 and add `meta generator` tag

Bootstrap 4.0 Beta 1 dropped the offset classes in favor of using margin utilities. Update the blog example in the docs to use the appropriate `ml-auto` instead of `offset-sm-1` class to retain a pixel perfect with previous versions.

Apply `align-items: center;` to `.input-group` instead of input group sub components, causes `.input-group .form-control` and `.input-group-addon` to be large when next to a tall element

the z-index was only corrected for `.modal.show` which made the modal drop behind the header and backdrop when fading out
simply dropping the `.show` from this selector will correct this issue

Re:  #23343 – **Broken Links on getbootstrap.com**

Clicking the `Examples` link in the Docs footer yields 404.

  http://getbootstrap.com/examples/

If merged, this makes the footer `Examples` link like the one in docs-navbar.html which is the same folder.

Therefore `_includes/footer.html` and `_includes/docs-navbar.html` now use the same link to `Examples`.

https://github.com/twbs/bootstrap/issues/22359

* docs: fix Popper.js name and removed comma

* docs: restore comma

https://github.com/twbs/bootstrap/issues/23291

.table-info should be .info in bootstrap 3

Before: 354 KB (363.514 bytes)
After:  129 KB (132.748 bytes)

tabs: fix nested tabs.

When one uses say a carousel inside a tab, the `.active` selector previously matches the carousel ones too leading to broken tabs.

It's not the perfect solution but should the job for now.

Also:

* compress them with SVGOMG
* add titles
* add `focusable="false"`