Rename border-radius-xxl variable and CSS custom property to 2xl

Co-authored-by: mdo <98681+mdo@users.noreply.github.com>

Author: Copilot

dist/css/bootstrap-reboot.css

@@ -163,7 +163,7 @@
   --#{$prefix}border-radius-sm: #{$border-radius-sm};
   --#{$prefix}border-radius-lg: #{$border-radius-lg};
   --#{$prefix}border-radius-xl: #{$border-radius-xl};
-  --#{$prefix}border-radius-xxl: #{$border-radius-xxl};
+  --#{$prefix}border-radius-2xl: #{$border-radius-2xl};
   --#{$prefix}border-radius-pill: #{$border-radius-pill};
   // scss-docs-end root-border-var
 

dist/css/bootstrap-reboot.css.map

@@ -214,7 +214,7 @@ $border-radius:               .375rem !default;
 $border-radius-sm:            .25rem !default;
 $border-radius-lg:            .5rem !default;
 $border-radius-xl:            1rem !default;
-$border-radius-xxl:           2rem !default;
+$border-radius-2xl:           2rem !default;
 $border-radius-pill:          50rem !default;
 // scss-docs-end border-radius-variables