Correct title on PDF image

Author: rocky

index.html

@@ -44,8 +44,8 @@ <h1>
 	  <div class="image">
 	    <a href="#doc">
               <img src="images/Mathics3-manual-page.png" height="300px" width="300px"
-		   alt="Mathics3 manual page screenshot"
-		   title="Mathics3 manual page screenshot">
+		   alt="Mathics3 User Manual PDF screenshot"
+		   title="Mathics3 User Manual PDF screenshot">
 	    </a>
 	  </div>
 	</div>