### 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
switch (p_statement->type) {
		case Node::ASSERT:
			print_assert(static_cast<AssertNode *>(p_statement));
			break;
		case Node::VARIABLE:
			print_variable(static_cast<VariableNode *>(p_statement));
			break;
		case Node::CONSTANT:
			print_constant(static_cast<ConstantNode *>(p_statement));
			break;
		case Node::IF:
			print_if(static_cast<IfNode *>(p_statement));
			break;
		case Node::FOR:
			print_for(static_cast<ForNode *>(p_statement));
			break;
		case Node::WHILE:
			print_while(static_cast<WhileNode *>(p_statement));
			break;
		case Node::MATCH:
			print_match(static_cast<MatchNode *>(p_statement));