summarize the other guides

static/build.html

@@ -43,6 +43,9 @@
                 <a href="#build">Build</a>
             </h1>
 
+            <p>This is a guide on building, modifying and contributing to GrapheneOS as a
+            developer.</p>
+
             <h2 id="table-of-contents">
                 <a href="#table-of-contents">Table of contents</a>
             </h2>

static/install.html

@@ -43,6 +43,9 @@
                 <a href="#install">Install</a>
             </h1>
 
+            <p>This is a guide on installing GrapheneOS for the officially supported devices. It
+            can be followed for both the official releases and custom builds.</p>
+
             <h2 id="table-of-contents">
                 <a href="#table-of-contents">Table of contents</a>
             </h2>