### 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)

push_error(R"*(Cannot use shorthand "get_node()" notation ("$") on a class that isn't a node.)*", p_get_node);
	}
	mark_lambda_use_self();
	p_get_node->set_datatype(result);
}
GDScriptParser::DataType GDScriptAnalyzer::make_global_class_meta_type(const StringName &p_class_name, const GDScriptParser::Node *p_source) {
	GDScriptParser::DataType type;
	String path = ScriptServer::get_global_class_path(p_class_name);
	String ext = path.get_extension();
	if (ext == GDScriptLanguage::get_singleton()->get_extension()) {
		Ref<GDScriptParserRef> ref = get_parser_for(path);
		if (ref.is_null()) {
			push_error(vformat(R"(Could not find script for class "%s".)", p_class_name), p_source);
			type.type_source = GDScriptParser::DataType::UNDETECTED;
			type.kind = GDScriptParser::DataType::VARIANT;
			return type;
		}
		Error err = ref->raise_status(GDScriptParserRef::INHERITANCE_SOLVED);
		if (err) {
			push_error(vformat(R"(Could not resolve class "%s", because of a parser error.)", p_class_name), p_source);
			type.type_source = GDScriptParser::DataType::UNDETECTED;
			type.kind = GDScriptParser::DataType::VARIANT;
			return type;
		}
		return ref->get_parser()->head->get_datatype();
	} else {
		return make_script_meta_type(ResourceLoader::load(path, "Script"));
	}
}
void GDScriptAnalyzer::reduce_identifier_from_base_set_class(GDScriptParser::IdentifierNode *p_identifier, GDScriptParser::DataType p_identifier_datatype) {