Allow namespaced variable in ask

[yelvert]

With the following task:

- prompt:
    msg:
      say: Whats up?
      ask: some_namespace.some_variable

I would expect the some_namespace.some_variable to be set, but instead I get the following error:

fatal: [localhost]: FAILED! => {"changed": false, "msg": "Invalid character in 'ask' parameter 'some_namespace.some_variable'."}

I have also tried it with some_namespace["some_variable"] and some_namespace['some_variable'] with the same error.