Small v6 Reboot updates (#42252)

* Fixes #41700: Remove moz-focus-inner

* Update more Reboot styles to remove button and select text-transform

Author: mdo

scss/content/_reboot.scss

@@ -441,11 +441,6 @@ $reboot-mark-tokens: defaults(
     line-height: inherit;
   }
 
-  // Remove the inheritance of text transform in Firefox
-  button,
-  select {
-    text-transform: none;
-  }
   // Set the cursor for non-`<button>` buttons
   //
   // Details at https://github.com/twbs/bootstrap/pull/30562
@@ -489,13 +484,6 @@ $reboot-mark-tokens: defaults(
     }
   }
 
-  // Remove inner border and padding from Firefox, but don't restore the outline like Normalize.
-
-  ::-moz-focus-inner {
-    padding: 0;
-    border-style: none;
-  }
-
   // 1. Textareas should really only resize vertically so they don't break their (horizontal) containers.
 
   textarea {
@@ -552,7 +540,8 @@ $reboot-mark-tokens: defaults(
     padding: 0;
   }
 
-  ::-webkit-inner-spin-button {
+  ::-webkit-inner-spin-button,
+  ::-webkit-outer-spin-button {
     height: auto;
   }
 

site/src/content/docs/migration.mdx

@@ -166,6 +166,8 @@ Bootstrap 6 is a major release with many breaking changes to modernize our codeb
 ### Reboot
 
 - Relocated heading classes (like `.h1`) and some type classes (`.mark` and `.small`) to Reboot from `_type.scss`. This avoids a dependency in Sass modules and we like to avoid extending selectors in general.
+- Removed the `::-moz-focus-inner` styles, as the pseudo selector is deprecated in Firefox.
+- Removed `text-transform: none` from `button` and `select` elements, as Firefox no longer incorrectly inherits text-transform.
 
 ### Forms