Add new interaction utilities and role attr to Reboot (#30562)

- Adds .user-select-* utils from v5
- Adds button role attribute util, one of the top requested features in our issues for adding pointer cursors
- Adds new docs page to demonstrate both
- Includes Sass list for customizing user select

scss/_reboot.scss

@@ -333,6 +333,13 @@ select {
   text-transform: none; // Remove the inheritance of text transform in Firefox
 }
 
+// Set the cursor for non-`<button>` buttons
+//
+// Details at https://github.com/twbs/bootstrap/pull/30562
+[role="button"] {
+  cursor: pointer;
+}
+
 // Remove the inheritance of word-wrap in Safari.
 //
 // Details at https://github.com/twbs/bootstrap/issues/24990

scss/_variables.scss

@@ -1138,6 +1138,7 @@ $pre-scrollable-max-height:         340px !default;
 $displays: none, inline, inline-block, block, table, table-row, table-cell, flex, inline-flex !default;
 $overflows: auto, hidden !default;
 $positions: static, relative, absolute, fixed, sticky !default;
+$user-selects: all, auto, none !default;
 
 
 // Printing

scss/utilities/_interactions.scss

@@ -0,0 +1,5 @@
+// stylelint-disable declaration-no-important
+
+@each $value in $user-selects {
+  .user-select-#{$value} { user-select: $value !important; }
+}