### Godot version

v4.0.beta13.official [caacade56]

### System information

Windows 8.1

### Issue description

The `Unreachable code (statement after return) in function 'function_name()'` warning is given for functions that do not have unreachable code. The same code does not give this warning in v3.5.stable.official [991bb6ac7].

### Steps to reproduce

```
func warning(i: int) -> void:
  if i == 0:
    pass
  elif i == 1:
    return
  else:
    return
  print("yeah")
```

Removing either the `elif` or the `else` removes the warning.

### Minimal reproduction project

N/A; code in reproduction steps can be placed in any blank gdscript file to trigger the error.
update_extents(assignment);
	make_completion_context(COMPLETION_ASSIGN, assignment);
#ifdef DEBUG_ENABLED
	bool has_operator = true;
#endif
	switch (previous.type) {
		case GDScriptTokenizer::Token::EQUAL:
			assignment->operation = AssignmentNode::OP_NONE;
			assignment->variant_op = Variant::OP_MAX;
#ifdef DEBUG_ENABLED
			has_operator = false;
#endif
			break;
		case GDScriptTokenizer::Token::PLUS_EQUAL:
			assignment->operation = AssignmentNode::OP_ADDITION;
			assignment->variant_op = Variant::OP_ADD;
			break;
		case GDScriptTokenizer::Token::MINUS_EQUAL:
			assignment->operation = AssignmentNode::OP_SUBTRACTION;
			assignment->variant_op = Variant::OP_SUBTRACT;
			break;
		case GDScriptTokenizer::Token::STAR_EQUAL:
			assignment->operation = AssignmentNode::OP_MULTIPLICATION;
			assignment->variant_op = Variant::OP_MULTIPLY;
			break;
		case GDScriptTokenizer::Token::STAR_STAR_EQUAL:
			assignment->operation = AssignmentNode::OP_POWER;
			assignment->variant_op = Variant::OP_POWER;
			break;
		case GDScriptTokenizer::Token::SLASH_EQUAL: