### 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
pop_multiline();
				complete_extents(call);
				return nullptr;
			}
			if (current_function->identifier) {
				call->function_name = current_function->identifier->name;
			} else {
				call->function_name = SNAME("<anonymous>");
			}
		} else {
			consume(GDScriptTokenizer::Token::PERIOD, R"(Expected "." or "(" after "super".)");
			make_completion_context(COMPLETION_SUPER_METHOD, call, true);
			if (!consume(GDScriptTokenizer::Token::IDENTIFIER, R"(Expected function name after ".".)")) {
				pop_multiline();
				complete_extents(call);
				return nullptr;
			}
			IdentifierNode *identifier = parse_identifier();
			call->callee = identifier;
			call->function_name = identifier->name;
			consume(GDScriptTokenizer::Token::PARENTHESIS_OPEN, R"(Expected "(" after function name.)");
		}
	} else {
		call->callee = p_previous_operand;
		if (call->callee == nullptr) {
			push_error(R"*(Cannot call on an expression. Use ".call()" if it's a Callable.)*");
		} else if (call->callee->type == Node::IDENTIFIER) {
			call->function_name = static_cast<IdentifierNode *>(call->callee)->name;
			make_completion_context(COMPLETION_METHOD, call->callee);
		} else if (call->callee->type == Node::SUBSCRIPT) {