Fix typo

Author: mdoutreluingne

reference/forms/types/money.rst

@@ -77,7 +77,7 @@ If set to ``true``, the HTML input will be rendered as a native HTML5
     As HTML5 number format is normalized, it is incompatible with ``grouping`` option.
 
 model_type
-~~~~~
+~~~~~~~~~~
 
 **type**: ``string`` **default**: ``float``