magic_gui char fields allow typing more than one character

[ctrueden]

In the Example_Script.js, there are a couple of character inputs. They should ideally be bounded such that only a single character can be specified, but in practice magic_gui currently allows more than one character to be typed.

I consider this an extremely low-priority issue to fix, as long as the first character of the strings entered are actually used as inputs to the module being executed.