### 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)

return resolve_class_inheritance(parser->head, true);
}
Error GDScriptAnalyzer::resolve_interface() {
	resolve_class_interface(parser->head, true);
	return parser->errors.is_empty() ? OK : ERR_PARSE_ERROR;
}
Error GDScriptAnalyzer::resolve_body() {
	resolve_class_body(parser->head, true);
	return parser->errors.is_empty() ? OK : ERR_PARSE_ERROR;
}
Error GDScriptAnalyzer::resolve_dependencies() {
	for (KeyValue<String, Ref<GDScriptParserRef>> &K : depended_parsers) {
		if (K.value.is_null()) {
			return ERR_PARSE_ERROR;
		}
		K.value->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
	}
	return parser->errors.is_empty() ? OK : ERR_PARSE_ERROR;
}
Error GDScriptAnalyzer::analyze() {