### 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)

continue;
			} else if (chr == '=') {
				foundNextEqual = true;
				assigned_value = line.right(current_index).strip_edges();
				assigned_value = assigned_value == "true" ? "false" : "true";
			} else {
				break;
			}
		}
		if (foundNextEqual) {
			line = line.substr(0, start) + "ignore_rotation =" + assigned_value + " # reversed \"rotating\" for Camera2D";
		}
	}
	// 
	if (line.contains("OS.get_ticks_msec")) {
		line = line.replace("OS.get_ticks_msec", "Time.get_ticks_msec");
	}
	if (line.contains("OS.get_ticks_usec")) {
		line = line.replace("OS.get_ticks_usec", "Time.get_ticks_usec");
	}
	if (line.contains("OS.get_unix_time")) {
		line = line.replace("OS.get_unix_time", "Time.get_unix_time_from_system");
	}
	if (line.contains("OS.get_datetime")) {
		line = line.replace("OS.get_datetime", "Time.get_datetime_dict_from_system");
	}
	// 
	if (line.contains("OS.get_display_cutouts")) {
		line = line.replace("OS.get_display_cutouts", "DisplayServer.get_display_cutouts");
	}