### 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)

reduce_expression(p_assert->condition);
	if (p_assert->message != nullptr) {
		reduce_expression(p_assert->message);
		if (!p_assert->message->get_datatype().has_no_type() && (p_assert->message->get_datatype().kind != GDScriptParser::DataType::BUILTIN || p_assert->message->get_datatype().builtin_type != Variant::STRING)) {
			push_error(R"(Expected string for assert error message.)", p_assert->message);
		}
	}
	p_assert->set_datatype(p_assert->condition->get_datatype());
#ifdef DEBUG_ENABLED
	if (p_assert->condition->is_constant) {
		if (p_assert->condition->reduced_value.booleanize()) {
			parser->push_warning(p_assert->condition, GDScriptWarning::ASSERT_ALWAYS_TRUE);
		} else if (!(p_assert->condition->type == GDScriptParser::Node::LITERAL && static_cast<GDScriptParser::LiteralNode *>(p_assert->condition)->value.get_type() == Variant::BOOL)) {
			parser->push_warning(p_assert->condition, GDScriptWarning::ASSERT_ALWAYS_FALSE);
		}
	}
#endif
}
void GDScriptAnalyzer::resolve_match(GDScriptParser::MatchNode *p_match) {
	reduce_expression(p_match->test);
	for (int i = 0; i < p_match->branches.size(); i++) {
		resolve_match_branch(p_match->branches[i], p_match->test);
		decide_suite_type(p_match, p_match->branches[i]);
	}
}
void GDScriptAnalyzer::resolve_match_branch(GDScriptParser::MatchBranchNode *p_match_branch, GDScriptParser::ExpressionNode *p_match_test) {