Incrementing variables by 1, ++, --

[enenbee]

I don't know if i'm adding this suggestion correctly, but it would be useful if in GDScript, like other programming languages, there could be a shorthand for incrementing / decrementing a variable by 1

[Calinou]

This is already being tracked in #2869. That said, this was already requested in godotengine/godot#1107 and it was rejected.