### 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)

if (to == -1) {
		to = arguments.size();
	}
	String value;
	if (arguments.size() > 0 && from != 0 && from < to) {
		value = ", ";
	}
	for (int i = from; i < to; i++) {
		value += arguments[i];
		if (i != to - 1) {
			value += ", ";
		}
	}
	return value;
}
String ProjectConverter3To4::get_starting_space(const String &line) const {