prompt_* should not add question mark

[friedelwolff]

Currently a question mark is added by prompt_bool() and prompt_choices() after the given prompt. Although this saves a character, it makes it impossible to provide a question without the question mark (like in other languages with different punctuation). Furthermore, I found it unintuitive to not write my question in full as I expect it to be presented to the user, and I guess a source reviewer will find my string without a question mark suspicious. Please consider not adding punctuation to the given prompt.

Thanks for flask-script!

[jirikuncar]

+1 I agree with @friedelwolff about the question mark. I think it's time to change this behavior.

[techniq]

I'd been a little hesitant to change the current behavior, but since the next release is already looking to cause some backward incompatibilities, might as well do some spring cleaning as well. @jirikuncar thanks for another pull request.