Add jekyll-redirect-from plugin in Gemfile, ohterwise report ".../jekyll/plugin_mannager.rb:29:in require: cannot load such file -- jekyll-redirect-from (LoadError)" when jekyll build

Add jquery cdn link

Fix "background-variants" anchor

Closes #17100

Closes #17091

reboot.scss typo  (shttp --> http)

v4 - fix after => :after

Correct presented class for outline buttons

v4 - Add display typography code example

Fixed a typo in buttons (disaabled)

Fix spelling mistake.

Fixed spelling mistake. Changed table of "ontents" to "Contents".

Fixed couple of formatting errors in modal.md (v4)

Fixed "Srollspy" typo in component title

V4 dev spelling fix in docs/getting-started/flexbox.md

tehter spelling

v4: Fix Typo in Forms docs

One extra `</p>` was out of place, plus couple of issues with `'s which caused some odd formatting.