Add information about resolver argument priority

Author: casahugo

controller/argument_value_resolver.rst

@@ -250,6 +250,7 @@ priority of 100. As this one is responsible for fetching attributes from the
 lower priority. This makes sure the argument resolvers are not triggered when
 the attribute is present. For instance, when passing the user along a
 sub-requests.
+However, if the argument is resolved from a request attribute, it is necessary to set a priority of at least 100 otherwise the resolver will not be executed.
 
 .. tip::