### Godot version

4.0 stable

### System information

Fedora, RX 590

### Issue description

I made a dictionary, and instead of using `:` to separate between key and value, i accidentally used `=`.
The error message was not clear at all `Parse Error: Expected identifier or string as LUA-style dictionary key.` 

I don't think assuming that people know how dictionaries are made in LUA is reasonable. And if this is not about LUA the programming language, i don't even know what this is about :D

I think this error should be replaced with something of the sort "Please use `:` as separator instead of `=` in your dictionary"

### Steps to reproduce

Paste this code in a script:

```

var dict = {
	1 = "lala"
}
```

Observe the error message
![image](https://user-images.githubusercontent.com/7917475/224549538-38ea25aa-ba75-431e-868b-0733a53b90ad.png)


### Minimal reproduction project

see above
case BinaryOpNode::OP_LOGIC_OR:
			push_text(" OR ");
			break;
		case BinaryOpNode::OP_CONTENT_TEST:
			push_text(" IN ");
			break;
		case BinaryOpNode::OP_COMP_EQUAL:
			push_text(" == ");
			break;
		case BinaryOpNode::OP_COMP_NOT_EQUAL:
			push_text(" != ");
			break;
		case BinaryOpNode::OP_COMP_LESS:
			push_text(" < ");
			break;
		case BinaryOpNode::OP_COMP_LESS_EQUAL:
			push_text(" <= ");
			break;
		case BinaryOpNode::OP_COMP_GREATER:
			push_text(" > ");
			break;
		case BinaryOpNode::OP_COMP_GREATER_EQUAL:
			push_text(" >= ");
			break;
	}
	print_expression(p_binary_op->right_operand);
	
	push_text(")");
}
void GDScriptParser::TreePrinter::print_call(CallNode *p_call) {