Clarify the usage of controller echo events

[Nintorch]

• Requires Add support for joypad echo events godot#117782 to be merged first.

This PR modifies the controller input tutorial to refer to the new project settings to enable the controller echo events. See the linked PR for more details.

[Nintorch]

Although now that I think about it, this will conflict with the way the main project setting is set up for new projects:

• input_devices/joypads/joypad_echo_events/send: If true, the engine will send joypad echo events after the user has pressed the joypad buttons or moved the joypad axes for long enough, false by default for existing projects and true by default for newly created projects;

We'll have to discuss it, maybe we can disable this project setting for newly created projects too.

[Calinou]

Explain why echo events are sometimes desired:

Suggested change

	Unlike keyboard input, holding down a controller button such as a D-pad direction or
	moving a controller axis over a specified deadzone will **not** by default
	generate repeated input events at fixed intervals (also known as "echo" events).
	This is because the operating system never sends "echo" events for controller input
	in the first place, and in Godot controller echo events are sent by the engine code.
	Unlike keyboard input, holding down a controller button such as a D-pad direction or
	moving a controller axis over a specified deadzone will **not** by default
	generate repeated input events at fixed intervals (also known as "echo" events).
	This can be an issue for user interfaces with sliders or long lists, as they
	become harder to navigate.
	This occurs because the operating system never sends "echo" events for controller
	input in the first place, and in Godot controller echo events are sent by the
	engine code.