* Prevent print utils from overriding all other display utils
Fixes#25221.
I agree with the referenced issue—this is unexpected and also causes a serious bug when mixed with other utility classes. This wasn't an issue in v3 given we had different utilities for hiding that weren't focused on display property.
* Add printing changes to migration docs
* unrelated heading sentence case change
* List out all .d-print- classes
— Moves print display utils to display utils file
— Removes all other .hidden- utils
— Expands on .invisible and it's mixin to provide options for visibility: visible and visibility: hidden
* Remove comment that duplicated some code
* Use transition mixin whenever possible
* Create a new function to reduce duplication
* Use the new `breakpoint-infix` method
* Clean up some utilities
- Align CSS properties
- In `_spacing.scss`, we had a comment saying what 'a' was for, but we removed that so this comment no longer applies
* Remove '-xs' from `.navbar-toggleable-xs` and remove duplication
* Fix outdated classes to use newer ones
* Explore responsive display utils, but with a twist: lowest breakpoint has no breakpoint modifier in the class name
* make floats use the same format, add float-none mixin
Mark Otto