`_is_in_input_hotzone` and `_is_in_output_hotzone` still refers to old theme constants

**Your Godot version:**
4.4.1

**Issue description:**
Both `port_grab_distance_horizontal` and `port_grab_distance_vertical` has been removed and the relevant theme constants are now `port_hotzone_inner_extent` and `port_hotzone_outer_extent`.

Description and sample code for both these functions(`_is_in_input_hotzone` and `_is_in_output_hotzone`) are still referring to the old variables.

**URL to the documentation page:**
https://docs.godotengine.org/en/stable/classes/class_graphedit.html