### 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)

rename_csharp_functions(source_lines, reg_container);
				rename_csharp_attributes(source_lines, reg_container);
				custom_rename(source_lines, "public class ", "public partial class ");
			} else if (file_name.ends_with(".gdshader") || file_name.ends_with(".shader")) {
				rename_common(RenamesMap3To4::shaders_renames, reg_container.shaders_regexes, source_lines);
			} else if (file_name.ends_with("tres")) {
				rename_classes(source_lines, reg_container); 
				rename_common(RenamesMap3To4::shaders_renames, reg_container.shaders_regexes, source_lines);
				rename_common(RenamesMap3To4::builtin_types_renames, reg_container.builtin_types_regexes, source_lines);
				custom_rename(source_lines, "\\.shader", ".gdshader");
			} else if (file_name.ends_with("project.godot")) {
				rename_common(RenamesMap3To4::project_godot_renames, reg_container.project_godot_regexes, source_lines);
				rename_common(RenamesMap3To4::builtin_types_renames, reg_container.builtin_types_regexes, source_lines);
				rename_input_map_scancode(source_lines, reg_container);
				rename_common(RenamesMap3To4::input_map_renames, reg_container.input_map_regexes, source_lines);
				custom_rename(source_lines, "config_version=4", "config_version=5");
			} else if (file_name.ends_with(".csproj")) {
				
			} else if (file_name.ends_with(".import")) {
				for (SourceLine &source_line : source_lines) {
					String &line = source_line.line;
					if (line.contains("nodes/root_type=\"Spatial\"")) {
						line = "nodes/root_type=\"Node3D\"";
					}
				}
			} else {
				ERR_PRINT(file_name + " is not supported!");
				continue;
			}
			for (SourceLine &source_line : source_lines) {