Merge pull request #1430 from processing/semantic-elements

Add <main> to all pages, add semantic HTML updates

Author: catarak

client/components/Nav.jsx

@@ -682,21 +682,12 @@ class Nav extends React.PureComponent {
     };
 
     return (
-      <nav className="nav" title="main-navigation" ref={(node) => { this.node = node; }}>
-        {this.renderLeftLayout(navDropdownState)}
-        {this.renderUserMenu(navDropdownState)}
-        {/*
-        <div className="nav__announce">
-          This is a preview version of the editor, that has not yet been officially released.
-          It is in development, you can report bugs <a
-            href="https://github.com/processing/p5.js-web-editor/issues"
-            target="_blank"
-            rel="noopener noreferrer"
-          >here</a>.
-          Please use with caution.
-        </div>
-      */}
-      </nav>
+      <header>
+        <nav className="nav" title="main-navigation" ref={(node) => { this.node = node; }}>
+          {this.renderLeftLayout(navDropdownState)}
+          {this.renderUserMenu(navDropdownState)}
+        </nav>
+      </header>
     );
   }
 }