Remedies GAR 1.6 violations (#5815)

Fixes #5790 go/GAR-web#headings

src/content/guides/index.md

@@ -21,7 +21,7 @@ To update these cards, edit src/_data/docs_cards.yml.
   {% capture index0Modulo3 %}{{ forloop.index0 | modulo:3 }}{% endcapture %}
   {% capture indexModulo3 %}{{ forloop.index | modulo:3 }}{% endcapture %}
   <div class="card">
-    <h3><a href="{{card.url}}">{{card.name}}</a></h3>
+    <h2><a href="{{card.url}}">{{card.name}}</a></h2>
     <p>{{card.description}}</p>
   </div>
 {% endfor -%}

src/content/guides/language/index.md

@@ -9,11 +9,11 @@ These two resources are popular with both beginning Dart developers and experts.
 
 <div class="card-grid">
   <div class="card">
-    <h3><a href="/language">Language tour</a></h3>
+    <h2><a href="/language">Language tour</a></h2>
     <p>A walk through all of the major features of the Dart language.</p>
   </div>
   <div class="card">
-    <h3><a href="/effective-dart">Effective Dart</a></h3>
+    <h2><a href="/effective-dart">Effective Dart</a></h2>
     <p>A set of guides on how to write the best Dart code
     possible. Guidelines cover style, documentation, usage,
     and design.</p>

src/content/resources/index.md

@@ -6,20 +6,19 @@ toc: false
 
 Check out the following Dart language resources:
 
-
 <div class="card-grid">
   <div class="card">
-    <h3><a href="/resources/books">Books</a></h3>
+    <h2><a href="/resources/books">Books</a></h2>
     <p>A collection of books about Dart.</p>
   </div>
 
   <div class="card">
-    <h3><a href="/code-of-conduct">Code of conduct</a></h3>
+    <h2><a href="/code-of-conduct">Code of conduct</a></h2>
     <p>Keeping community spaces safe and respectful.</p>
   </div>
 
   <div class="card">
-    <h3><a href="/resources/videos">Videos</a></h3>
+    <h2><a href="/resources/videos">Videos</a></h2>
     <p>Videos aimed at Dart developers.</p>
   </div>
 </div>