docs(site): add examples/README links (#3099)

Tested on desktop and mobile.

Author: isaaccloos

_layouts/guide.html

@@ -32,10 +32,12 @@ <h1>{{ page.title }}</h1>
               {% assign topic = site.data.contrib | first %}
               {% include guide_ul.html topic=topic %}
             {% endif %}
-            <h4 class="guide-topic-title">
+            <h4 class="guide-links">
               {% if page.collection == "legacy" %}
+                <a href="{{ site.legacy_examples_url }}/README.md">Additional Examples</a>
                 <a href="{{ site.legacy_docs_url }}">API Reference</a>
               {% elsif page.collection == "stable" %}
+                <a href="{{ site.examples_url }}/README.md">Additional Examples</a>
                 <a href="{{ site.docs_url }}">API Reference</a>
               {% endif %}
             </h4>

css/main.scss

@@ -146,6 +146,16 @@ pre code {
     font-size: 1.1rem;
 }
 
+.hyper-sidebar .guide-links {
+    display: flex;
+    flex-direction: column;
+    font-size: 1.1rem;
+}
+
+.hyper-sidebar .guide-links a:not(:last-child) {
+    margin-bottom: 1rem;
+}
+
 .hyper-sidebar .nav {
     display: block;
     margin-bottom: 2rem;