fix cover.jpg image path

Author: sspickle

ide/templates/index.html

@@ -51,7 +51,7 @@ <h2>Web VPython</h2>
 
         <div style="position:relative;width:100%;padding:3px;">
 
-        <img src="../docs//VPythonDocs/_images/cover.jpg" width="226" height="240" class="right">
+        <img src="/docs/VPythonDocs/_images/cover.jpg" width="226" height="240" class="right">
 
         <p>VPython is an easy-to-use, powerful environment for creating 3D animations.
         Here at glowscript.org (or <a href=https://glowscript.org>webvpython.org</a>, which takes you here),