Enforce Signal parameter types in Connect

[jordi-star]

Beginning work for Typed signals.
Adds get_method_info() to Callable (not exposed to Godot) for retrieving Callable arg info.

Object's connect method now checks if the correct amount of non-initialized arguments exist in the callable, and if the types are equal (todo: Check if types are compatible instead). Currently only implemented in connect

Task list:

• Check if types are compatible instead of doing explicit ==

• Add checks in the analyzer to error ahead of time when connect uses a non-compatible Callable

• Rewrite messages for readability

• Clean-up code

• Write tests

Example

extends Node2D

signal typed(arg1:bool, arg2:int);

func incorrect_arg_amount(arg1:Vector2):
	pass

func incorrect_arg_types(arg1:Node, arg2:String):
	pass

func _ready():
	push_warning("Incorrect arg amount");
	typed.connect(incorrect_arg_amount);
	push_warning("Incorrect arg types");
	typed.connect(incorrect_arg_types);
	
	push_warning("Lambdas are also checked, of course.");
	typed.connect(func(arg1:String):
		pass
	);

Bugsquad edit: This closes godotengine/godot-proposals#2557 and closes #54333.

[jordi-star]

Parameter types do not need to be enforced in emit because all connections are forced to have the correct arguments anyways. Callable already implements an error when the wrong arguments are provided when called.

[jordi-star]

Analyzer now checks if the provided callable contains the correct arguments for the provided signal. I'm gonna go over the code I have right now, see if any changes are needed, then write tests.