### 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)

ERR_FAIL_COND_V_MSG(project_godot_content.contains(conventer_text), false, "Project already was converted with this tool.");
	}
	Vector<String> collected_files = check_for_files();
	uint32_t converted_files = 0;
	
	for (int i = 0; i < collected_files.size(); i++) {
		String file_name = collected_files[i];
		Vector<String> lines;
		uint32_t ignored_lines = 0;
		uint64_t file_size = 0;
		{
			Ref<FileAccess> file = FileAccess::open(file_name, FileAccess::READ);
			ERR_CONTINUE_MSG(file.is_null(), vformat("Unable to read content of \"%s\".", file_name));
			while (!file->eof_reached()) {
				String line = file->get_line();
				file_size += line.size();
				lines.append(line);
			}
		}
		print_line(vformat("Checking for conversion - %d/%d file - \"%s\" with size - %d KB", i + 1, collected_files.size(), file_name.trim_prefix("res://"), file_size / 1024));
		Vector<String> changed_elements;
		Vector<String> reason;
		bool is_ignored = false;
		uint64_t start_time = Time::get_singleton()->get_ticks_msec();
		if (file_name.ends_with(".shader")) {
			reason.append("\tFile extension will be renamed from \"shader\" to \"gdshader\".");
		}
		if (file_size < uint64_t(maximum_file_size)) {
			if (file_name.ends_with(".gd")) {
				changed_elements.append_array(check_for_rename_classes(lines, reg_container));