making interpolate/evaluate more clear.

index.html

@@ -1112,6 +1112,8 @@ compiled({epithet: "stooge"});
         template settings to use different symbols to set off interpolated code.
         Define an <b>interpolate</b> regex, and an (optional) <b>evaluate</b> regex
         to match expressions that should be inserted and evaluated, respectively.
+        If no <b>evaluate</b> regex is provided, your templates will only be 
+        capable of interpolating values. 
         For example, to perform
         <a href="http://github.com/janl/mustache.js#readme">Mustache.js</a>
         style templating: