Unfocus LineEdit when pressing Escape

[KoBeWi]

Closes godotengine/godot-proposals#7543

[akien-mga]

Makes sense to me.

More reviews from @godotengine/gui-nodes welcome.

[akien-mga]

Thanks!

[Calinou]

Would this make sense to do for TextEdit as well? It might be an issue for autocompletion users, so it'll surely have to be optional there. (I'd say it should be enabled by default still – we can disable it for specific things such as the script/shader editor.)

[KoBeWi]

It could be used for multiline fields in the inspector, so IMO makes sense. (I also have a plugin that would benefit from this)

[nathanfranke]

Probably should use accept_event(), this stops _unhandled_input from also being called for escape.

# gdscript not C++, but this works as expected on LineEdit
func _gui_input(event: InputEvent) -> void:
	if event.is_action(&"ui_cancel"):
		release_focus()
		accept_event()

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Otherwise, if I have escape on unhandled input to reload current scene, I get this (separate bug?),

E 0:00:01:0304   release_focus: Condition "!is_inside_tree()" is true.
  <C++ Source>   scene/gui/control.cpp:2018 @ release_focus()

MRP:

func _unhandled_input(event: InputEvent) -> void:
	if event.is_action_pressed(&"ui_cancel"):
		get_tree().reload_current_scene()
# plus LineEdit somewhere

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(Also, TextEdit makes sense yes)