### 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)

Ref<DirAccess> dir = DirAccess::open(path);
		if (dir.is_valid()) {
			dir->set_include_hidden(true);
			dir->list_dir_begin();
			String current_dir = dir->get_current_dir();
			String file_name = dir->_get_next();
			while (file_name != "") {
				if (file_name == ".git" || file_name == ".godot") {
					file_name = dir->_get_next();
					continue;
				}
				if (dir->current_is_dir()) {
					directories_to_check.append(current_dir.path_join(file_name) + "/");
				} else {
					bool proper_extension = false;
					if (file_name.ends_with(".gd") || file_name.ends_with(".shader") || file_name.ends_with(".gdshader") || file_name.ends_with(".tscn") || file_name.ends_with(".tres") || file_name.ends_with(".godot") || file_name.ends_with(".cs") || file_name.ends_with(".csproj") || file_name.ends_with(".import"))
						proper_extension = true;
					if (proper_extension) {
						collected_files.append(current_dir.path_join(file_name));
					}
				}
				file_name = dir->_get_next();
			}
		} else {
			print_verbose("Failed to open " + path);
		}
	}
	return collected_files;
}
Vector<SourceLine> ProjectConverter3To4::split_lines(const String &text) {