Expand M291 user input prompts

[Phaedrux]

M291 can already be used to prompt the user to jog an axis, but could this be expanded to further parameters such as temperature or fan speed?

I make heavy use of M291 in my macros and it would be nice to be able to prompt for more things.

[T3P3Tony]

@phaedrux I can see this eventually turning into a dialog box builder that would allow you to specify which Gcode you were wanting to promt the user to complete (e.g. M106) and then which variables (e.g. P<n> S<n>) and then a range of valid values for P and S...

Eventually we will have completed the quest to turn Gcode into a complete programming language... j/k

[Phaedrux]

Why does this make me picture moving a little turtle across the screen?