build(docs-infra): improve directive selector rendering (#25768)

`:not(...)` blocks are now rendered as italic, while the
rest of the selector is bold.

PR Close #25768

aio/src/styles/2-modules/_api-pages.scss

@@ -116,7 +116,16 @@
     }
   }
 
-  .property-name {
+  .selector-list {
+    li, a {
+      font-weight: bold;
+      i {
+        font-weight: normal;
+      }
+    }
+  }
+
+  .member-name {
     font-weight: bold;
   }
 }

aio/tools/transforms/templates/api/includes/selectors.html

@@ -6,7 +6,7 @@
   {% else %}
   <ul>
     {%- for selector in doc.selectorArray %}
-    <li><code>{$ selector $}</code></li>
+    <li><code>{$ selector | replace(r/(:not\([^()]+\))/g, '<i>$1</i>') $}</code></li>
     {% endfor %}
   </ul>
   {% endif %}