* Follow-up to #29095

This PR fixes the responsive containers that were added in #29095, originally stubbed out in #25631. Apologies to @browner12 for getting that wrong.

Fixes #25631.

* update navbar as well because we cannot reset all containers uniformly

* Update navbars example to include container-xl example to ensure containers match

* rewrite responsive containers docs, add table of max-widths

* Update container docs
- Move table up to the intro
- Remove the container example because it's actually hella confusing
- Update and link to grid example as a demo instead

* create responsive containers

provide more flexibility and allow the user to determine when containers switch from fluid to fixed width.

* fix the base container code

this commit fixes the non-media portion of the generated CSS. I learned about the `@extends` directive and was able to put it to good use.

I create a new temporary map that contains all the main `$container-max-widths` and join it to our 2 special cases of 'xs' and 'fluid'.  Then we loop through that and, with the appropriate infixes, extend our placeholder

* formatting for style

forgot to run my tests before the last push, i think these are better.

* finish incomplete comment

* fix the responsive containers

using the `@extend` directive I was able to clean up this code

* fix responsive containers in the navbar

mostly we just look through all of our breakpoints so we can include all of the responsive container classes in the tweaks we have to do for the navbar (redeclaring flex properties...

"Popovers whose both title..."

Backport of #29140

For Gradient, We have to use the background-image instead of only background.

Fixed minor grammatical error:

"... the best method get scroll ..."

=>

"... the best method to get scroll ..."

allow dynamic modal body for scrollable modals

* Update bs-custom-file-input.min.js to v1.3.2.
* Update anchor.min.js to v4.2.0.

Remove https://glyph.smarticons.co/ from list of suggestions.
The domain is now for sale and is triggers warnings in Firefox and Chrome

This might fix the build failures we are getting.

Adapted for v4-dev.

For some reason the old image was bad quality.

Change `word-break: break-word;` to `word-wrap: break-word;`