This reuses the existing URLs in the docs Jekyll configuration rather than hard coding.

Refs #17913
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v4 docs Missed navbar color scheme name changes

Change d6b6a20a missed two doc mentions
of the previous names when changing to new:
    .navbar-default  -->  .navbar-light
    .navbar-inverse  -->  .navbar-dark

Refs #15947
Somehow c256aca1 got lost during the SCSS translation...

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Replace ZeroClipboard with clipboard.js.

Things left:
1. clear the selection after copy
2. add messages for success and error

Also one spelling typo corrected.

Closes #18043

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Refs b6e6a05b
We ought to re-check this for iOS 9.1 at some point...

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Add SRI hashes to CDN links in docs

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Stop hardcoding grid tiers in flexbox alignment & ordering classes

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Stop hardcoding grid breakpoints in responsive alignment utility classes

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v4 - Remove unused sass_repo variable

Per https://github.com/twbs/bootstrap/pull/17997#discussion_r42564175 ; thanks @vsn4ik !
Refs #17769
/fyi @croaky

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v4 - Update grunt-jscs to 2.1.0 to use JSCS 2.x

Fix three small typos

Add #17913 to Wall of Browser Bugs

Refs https://code.google.com/p/chromium/issues/detail?id=544290
Refs https://bugs.webkit.org/show_bug.cgi?id=150271
Closes #17913
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Fix typo in docs for tooltips.

Remove redundant `<span class="sr-only">...</span>` for close buttons

Since `aria-label` is used, it's not necessary anymore.

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