Wrong Documentation on Signal item_selected from OptionButton

[viniciusaportela]

Godot version:
3.2.stable

OS/device including version:
Windows 10 18363

Issue description:
On docs show that the signal item_selected from OptionButton has the ID parameter when it actually the Index, that's a small thing but it really confused me at first that passed over 30 min trying to figure out what was wrong (cause I used the id to be the same to index)

Steps to reproduce:

1. Create the nodes

2. Create the items

3. Connect item_select

$Option.connect("item_selected", self, 'on_option_changed')

4. Start Clicking

Minimal reproduction project:

extends Control

func _ready():
	$Option.connect("item_selected", self, 'on_option_changed')
	$Option.remove_item(0)

func on_option_changed(idx):
	print('item changed')
	print(idx)

Selecting from bottom to top it returns:

Not 30, 20, 10 as expected

[aaronfranke]

Yes, I can confirm that "id" should be changed to "index" in option_button.cpp line 344, but I don't know if the same should be done for item_focused.

However, while testing, I encountered really weird behavior.

Code:

func on_option_changed(idx):
	print('item changed')
	print(idx)
	print($Option.get_selected_id())
	print($Option.get_item_id(idx))
	print($Option.get_item_index($Option.get_item_id(idx)))

Output:

item changed
1
20
20
1
item changed
0
10
10
0

Seems that the index in the item list editor does not match up with the index at runtime. The item with an ID of 20 has an index of 2 in the editor, but when selected, it has an index of 1. I'm also unable to reselect "Item 0" with an ID of 0.

[zak-grumbles]

Submitted merge request #37303 as a fix for this, although the changes only cover fixing documentation and the ADD_SIGNAL call in code and do not address the editor-runtime index mismatch.