add comments for value option

src/element/editable-element.js

@@ -599,6 +599,18 @@ Makes editable any HTML element on the page. Applied as jQuery method.
         autotext: 'auto', 
         /**
         Initial value of input. If not set, taken from element's text.  
+        Note, that if element's text is empty - text is automatically generated from value and can be customized (see `autotext` option).  
+        For example, to display currency sign:
+        @example
+        <a id="price" data-type="text" data-value="100"></a>
+        <script>
+        $('#price').editable({
+            ...
+            display: function(value) {
+              $(this).text(value + '$');
+            } 
+        }) 
+        </script>
                 
         @property value 
         @type mixed