Removing complex padding calc on kbd

Author: jonrohan

src/base/kbd.scss

@@ -3,7 +3,7 @@
 
 kbd {
   display: inline-block;
-  padding: calc(var(--base-size-4) - 1) calc(var(--base-size-4) + 1);
+  padding: var(--base-size-4);
   font: 11px $mono-font;
   // stylelint-disable-next-line primer/typography
   line-height: 10px;