change note in .resizable() mixin for accuracy

Not a Safari bug. It's standards-compliant.

Quoting from http://www.w3.org/TR/css3-ui/#resize :
> ### 8.1. `resize` property
>
> * Applies to: elements with `overflow` other than `visible`
>
> The `resize` property applies to elements whose computed `overflow` value is something other than `visible`.

Original comment was added in commit 648c4689273647c321dd6e3979d910282e9a9339.
more precise docs link
reference other more recent source regarding the IE viewport bug
docs: sort tooltip & container options for sanity
add 'viewport' option to popover docs; #12328 erratum
add multiple triggers info to popover docs
add 'selector' option motivation to tooltip docs
add 'container' option motivation to tooltip docs
update default 'template' value in popover docs
Merge pull request #13601 from twbs/tooltip-popover-doc

Sync tooltip & popover docs
add `target` option to Affix plugin
Merge branch 'impl-13342'; Closes #13342.
Merge pull request #13600 from twbs/resize-note-correction

change note in .resizable() mixin for accuracy
update link to Grunt setup & info