fix: minor wording changes

Author: lowlighter

.github/labeler.yml

@@ -1,5 +1,5 @@
-# Meta files
-meta:
+# Repository files
+repo:
   - changed-files:
       - any-glob-to-any-file:
           - .devcontainer/**

package-lock.json

@@ -6,7 +6,7 @@ <h2>
       Plug-and-play
     </h2>
     <p>
-      Simply <a href="#usage">include the library</a> and start building amazing things instantly with vanilla JavaScript and HTML.
+      Simply <a href="#usage">include the library</a> and start building amazing things instantly with vanilla JavaScript expressions and HTML.
     </p>
   </div>
   <div>

www/html/mizu/features.html

@@ -1,4 +1,12 @@
 <!-- deno-fmt-ignore-file -->
+<section>
+  <div class="flash attention">
+    <p>
+      The playground is still experimental.<br>
+      <small>Please report any issues or feedback on <a href="https://github.com/lowlighter/mizu/issues/41">github.com/lowlighter/mizu/issues/41</a>.</small>
+    </p>
+  </div>
+</section>
 <div class="playground demo" data-color-scheme="dark">
   <div class="mockups">
     <div class="mockup browser">