Fix .stretched-link buttons, clipped table dropdowns and alert icon docs (#3102)

Co-authored-by: copilot-swe-agent[bot] <198982749+Copilot@users.noreply.github.com>

core/scss/helpers/_index.scss

@@ -41,6 +41,11 @@
     z-index: 1;
     content: '';
   }
+
+  // .btn is positioned, which would make the button itself the containing block
+  &.btn {
+    position: static;
+  }
 }
 
 //