Support different line heights for buttons.

Author: LunicLynx

scss/_buttons.scss

@@ -199,9 +199,9 @@
 //
 
 .btn-lg {
-  @include button-size($btn-padding-y-lg, $btn-padding-x-lg, $btn-font-size-lg, $btn-border-radius-lg);
+  @include button-size($btn-padding-y-lg, $btn-padding-x-lg, $btn-font-size-lg, $btn-border-radius-lg, $btn-line-height-lg);
 }
 
 .btn-sm {
-  @include button-size($btn-padding-y-sm, $btn-padding-x-sm, $btn-font-size-sm, $btn-border-radius-sm);
+  @include button-size($btn-padding-y-sm, $btn-padding-x-sm, $btn-font-size-sm, $btn-border-radius-sm, $btn-line-height-sm);
 }

scss/_variables.scss

@@ -787,10 +787,12 @@ $input-btn-focus-box-shadow:    $focus-ring-box-shadow !default;
 $input-btn-padding-y-sm:      .25rem !default;
 $input-btn-padding-x-sm:      .5rem !default;
 $input-btn-font-size-sm:      $font-size-sm !default;
+$input-btn-line-height-sm:    $line-height-sm !default;
 
 $input-btn-padding-y-lg:      .5rem !default;
 $input-btn-padding-x-lg:      1rem !default;
 $input-btn-font-size-lg:      $font-size-lg !default;
+$input-btn-line-height-lg:    $line-height-lg !default;
 
 $input-btn-border-width:      var(--#{$prefix}border-width) !default;
 // scss-docs-end input-btn-variables
@@ -811,10 +813,12 @@ $btn-white-space:             null !default; // Set to `nowrap` to prevent text
 $btn-padding-y-sm:            $input-btn-padding-y-sm !default;
 $btn-padding-x-sm:            $input-btn-padding-x-sm !default;
 $btn-font-size-sm:            $input-btn-font-size-sm !default;
+$btn-line-height-sm:          $input-btn-line-height-sm !default;
 
 $btn-padding-y-lg:            $input-btn-padding-y-lg !default;
 $btn-padding-x-lg:            $input-btn-padding-x-lg !default;
 $btn-font-size-lg:            $input-btn-font-size-lg !default;
+$btn-line-height-lg:          $input-btn-line-height-lg !default;
 
 $btn-border-width:            $input-btn-border-width !default;
 

scss/mixins/_buttons.scss

@@ -61,10 +61,11 @@
 // scss-docs-end btn-outline-variant-mixin
 
 // scss-docs-start btn-size-mixin
-@mixin button-size($padding-y, $padding-x, $font-size, $border-radius) {
+@mixin button-size($padding-y, $padding-x, $font-size, $border-radius, $line-height) {
   --#{$prefix}btn-padding-y: #{$padding-y};
   --#{$prefix}btn-padding-x: #{$padding-x};
   @include rfs($font-size, --#{$prefix}btn-font-size);
+  --#{$prefix}btn-line-height: #{$line-height};
   --#{$prefix}btn-border-radius: #{$border-radius};
 }
 // scss-docs-end btn-size-mixin