v4 Alpha 4 ship list

[mdo]

Summary of changes

A small "alpha patch" to address the npm package from not having any JS files and incorporate a few small changes to our CSS and docs.

CSS

• Contextual background-inverse text color fix #20130: Make .bg-inverse use the background variant mixin for proper text color.
• Progress bar:fix use variable progress-border-radius instead of border-radius #20333: Update progress bar to use $progress-border-radius instead of $border-radius.
• Update variable usage for input group addon #20387: Use $input-border-radius-* variables on .input-group-addons instead of $border-radius.
• Remove unused $size parameter #20413: Remove unused $size parameter from grid mixin.
• Make .card class inside .card-columns display: block too #20447: Make cards block level in columns.
• Invalid US-ASCII character "\xE2" in v4Alpha3.0 #20469: Remove non ASCII character from table CSS.
• Cannot use other units than 'px' for $alert-padding variable #20485: Use rem units on Alert's dismiss icon.
• v4: Remove media margin #20545: Removed the inconsistent margins between flex and non-flex modes from .media. Replaced them with spacing utils in our docs examples.
• Remove unused $variables in grid mixins #20597: Removed unused variables in some grid mixins.
• v4: a.text-muted:hover broken #20619: Ensure hover effects work on text utilities.
• v4: Consistent checkbox and radio markup #20629: Update form checkbox and radio styles for validation; tweak docs to match.

Docs

• Migration docs: Fix typo in 'Reboot' about units #20282: Fix typo in Migration docs about Reboot and unit changes.
• Docs Tooltip Static Demo uses v3 class names #20341: Update static tooltip demo in docs to use proper class names.
• Import the flexbox utilities into the docs flex stylesheet #20417: Import the flexbox utilities into the docs flex stylesheet to fix broken flex utility docs.
• Updated docs with extra auto resize example #20475: Update flexbox grid docs to show auto-sizing of sibling columns when using a centered, odd-count column.
• Remove CDN "not yet available" notice. #20476: Remove CDN coming soon notice from docs page.
• Input Group Segemented Button Icon Spacing #20484, Fix segmented buttons in input group docs #20489: Fix segmented button in input group examples.
• Renamed contextual classes for tables #20505: Update migration guidelines for renamed table variants.
• Added information about the .panel-group class #20519: Add migration note about .panel-group.
• Fixes #20495 #20551: Ensure progress component table of contents renders.
• v4: Split dropup button example #20553: Properly size split dropup variation with modifier class.

Packaging

• js/ directory missing from v4 alpha 3 on npm #20385, v4: Fix npm JS directory #20418: Fix for npm not having a JS directory.
• Fix package.json #20394: Point package.json's main to proper JS file for package managers.