### 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)

line = line.replace("get_focus_owner()", "get_viewport().gui_get_focus_owner()");
	}
	// 
	if (line.contains(".pressed")) {
		int start = line.find(".pressed");
		bool foundNextEqual = false;
		String line_to_check = line.substr(start + String(".pressed").length());
		for (int current_index = 0; line_to_check.length() > current_index; current_index++) {
			char32_t chr = line_to_check.get(current_index);
			if (chr == '\t' || chr == ' ') {
				continue;
			} else if (chr == '=') {
				foundNextEqual = true;
			} else {
				break;
			}
		}
		if (foundNextEqual) {
			line = line.substr(0, start) + ".button_pressed" + line.substr(start + String(".pressed").length());
		}
	}
	// 
	if (contains_function_call(line, "rotating")) {
		int start = line.find("rotating");
		bool foundNextEqual = false;
		String line_to_check = line.substr(start + String("rotating").length());
		String assigned_value;
		for (int current_index = 0; line_to_check.length() > current_index; current_index++) {
			char32_t chr = line_to_check.get(current_index);
			if (chr == '\t' || chr == ' ') {