### Godot version

v4.0.rc1.official [8843d9ad3]

### System information

Lubuntu

### Issue description

You can't use + or += to mutate typed arrays.

It seems to be not correctly getting the type information from the second operand.

An erudite poster on the discord puts it differently:
> it's more like operator + doesn't retain Array typing
> the syntax for Array Concatenation via operators, but the idea gets across i think


The error you see is:
```Trying to assign an array of type "Array" to a variable of type "Array[int]".```


### Steps to reproduce

```
	var Alice: Array[int] = [1,2,3]
	var Bob: Array[int] = [4,5,6]
	Alice += Bob
```
This will crash with the above error message.

### Minimal reproduction project

[plus_syntax_broken_demo_project.zip](https://github.com/godotengine/godot/files/10694514/plus_syntax_broken_demo_project.zip)

parser->errors.clear();
	Error err = OK;
	err = resolve_inheritance();
	if (err) {
		return err;
	}
	
	for (GDScriptParser::AnnotationNode *&E : parser->head->annotations) {
		resolve_annotation(E);
		E->apply(parser, parser->head);
	}
	resolve_interface();
	resolve_body();
	if (!parser->errors.is_empty()) {
		return ERR_PARSE_ERROR;
	}
	return resolve_dependencies();
}
GDScriptAnalyzer::GDScriptAnalyzer(GDScriptParser *p_parser) {
	parser = p_parser;
}