### Godot version

4.0.2.stable

### System information

Ubuntu 22.10

### Issue description

This happens when converting a godot3 project to a godot4 project.
Godot3 source
```gdscript
extends Node2D

export(int) var integer := 2
export(Resource) var resource: Resource = null
```

Result
```gdscript
extends Node2D

@export var integer: int := 2
@export var resource: Resource: Resource = null
```

Expected result
```gdscript
extends Node2D

@export var integer := 2
@export var resource: Resource = null
```

If someone can point to where in the code this might be fixed maybe I can fix it myself, sounds like a good first issue.


### Steps to reproduce

Open the given project (or any project really) and convert it to a godot 4 project

### Minimal reproduction project

[Conversion Tool Typing Problem.zip](https://github.com/godotengine/godot/files/11185334/Conversion.Tool.Typing.Problem.zip)

valid = valid && test_conversion_with_regex("AAA Color.white AF", "AAA Color.WHITE AF", &ProjectConverter3To4::rename_colors, "custom rename", reg_container);
	
	valid = valid && test_conversion_with_regex("\"device\":-1,\"scancode\":16777231,\"physical_scancode\":16777232", "\"device\":-1,\"scancode\":4194319,\"physical_scancode\":4194320", &ProjectConverter3To4::rename_input_map_scancode, "custom rename", reg_container);
	valid = valid && test_conversion_with_regex("\"device\":-1,\"scancode\":65,\"physical_scancode\":66", "\"device\":-1,\"scancode\":65,\"physical_scancode\":66", &ProjectConverter3To4::rename_input_map_scancode, "custom rename", reg_container);
	
	{
		String from = "instance";
		String to = "instantiate";
		String name = "AA.instance()";
		Vector<SourceLine> got = split_lines(name);
		String expected = "AA.instantiate()";
		custom_rename(got, from, to);
		String got_str = collect_string_from_vector(got);
		if (got_str != expected) {
			ERR_PRINT(vformat("Failed to convert custom rename \"%s\" to \"%s\", got \"%s\", instead.", name, expected, got_str));
		}
		valid = valid && (got_str == expected);
	}
	
	{
		{ String base = "var roman = kieliszek.";
	String expected = "kieliszek.";
	String got = get_object_of_execution(base);
	if (got != expected) {
		ERR_PRINT(vformat("Failed to get proper data from get_object_of_execution. \"%s\" should return \"%s\"(%d), got \"%s\"(%d), instead.", base, expected, expected.size(), got, got.size()));
	}
	valid = valid && (got == expected);
}
{
	String base = "r.";