added to index, small fix

Resources/doc/index.rst

@@ -25,6 +25,7 @@ Reference Guide
    reference/routing
    reference/saving_hooks
    reference/form_types
+   reference/form_help_message
    reference/field_types
    reference/conditional_validation
    reference/templates

Resources/doc/reference/form_help_message.rst

@@ -1,10 +1,10 @@
 Form Help Messages
 ==========
 
-About Help messages
+Help Messages
 ------------------------
 
-Help messages are short notes that are rendered together with form fields. They are generally used to show additional information so the user can complete the form-element faster and more accurately.
+Help messages are short notes that are rendered together with form fields. They are generally used to show additional information so the user can complete the form element faster and more accurately.
 
 Example
 ----------------
@@ -24,7 +24,7 @@ Example
         }
     }
 
-Alternative way to define help message
+Alternative Way To Define Help Messages
 ----------------
 
 .. code-block:: php