docs: widen search expansion without collapsing header title/version

Author: jijo-OO7

docs/stylesheets/extra.css

@@ -690,7 +690,7 @@ a.md-header__button.md-logo img {
   }
 
   .md-search__inner {
-    max-width: 19rem;
+    max-width: 32rem;
   }
 
   .md-search__input {