fix HTML 5 info notes related to hamburger-icon images

1988/isaak/index.html

@@ -197,8 +197,7 @@
         src="../../png/hamburger-icon-open.png"
         alt="hamburger style menu icon - open state"
         width=48
-        height=48
-      />
+        height=48>
     </button>
 
     <button id="header-close-menu-button" class="hide-content">
@@ -206,8 +205,7 @@
         src="../../png/hamburger-icon-closed.png"
         alt="hamburger style menu icon - closed state"
         width=48
-        height=48
-      />
+        height=48>
     </button>
 
     <div id="mobile-menu-panel" class="hide-content">