### 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)

reduced = Vector2i(args[0], args[1]);
								break;
							case 3:
								reduced = Vector3i(args[0], args[1], args[2]);
								break;
						}
						p_for->list->is_constant = true;
						p_for->list->reduced_value = reduced;
					}
				}
				if (p_for->list->is_constant) {
					p_for->list->set_datatype(type_from_variant(p_for->list->reduced_value, p_for->list));
				} else {
					GDScriptParser::DataType list_type;
					list_type.type_source = GDScriptParser::DataType::ANNOTATED_EXPLICIT;
					list_type.kind = GDScriptParser::DataType::BUILTIN;
					list_type.builtin_type = Variant::ARRAY;
					p_for->list->set_datatype(list_type);
				}
			}
		}
	}
	GDScriptParser::DataType variable_type;
	if (list_resolved) {
		variable_type.type_source = GDScriptParser::DataType::ANNOTATED_INFERRED;
		variable_type.kind = GDScriptParser::DataType::BUILTIN;
		variable_type.builtin_type = Variant::INT;
	} else if (p_for->list) {
		resolve_node(p_for->list, false);
		GDScriptParser::DataType list_type = p_for->list->get_datatype();