### 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
SuiteNode *else_block = alloc_node<SuiteNode>();
		else_block->parent_function = current_function;
		else_block->parent_block = current_suite;
		SuiteNode *previous_suite = current_suite;
		current_suite = else_block;
		IfNode *elif = parse_if("elif");
		else_block->statements.push_back(elif);
		complete_extents(else_block);
		n_if->false_block = else_block;
		current_suite = previous_suite;
	} else if (match(GDScriptTokenizer::Token::ELSE)) {
		consume(GDScriptTokenizer::Token::COLON, R"(Expected ":" after "else".)");
		n_if->false_block = parse_suite(R"("else" block)");
	}
	complete_extents(n_if);
	if (n_if->false_block != nullptr && n_if->false_block->has_return && n_if->true_block->has_return) {
		current_suite->has_return = true;
	}
	if (n_if->false_block != nullptr && n_if->false_block->has_continue) {
		current_suite->has_continue = true;
	}
	return n_if;
}
GDScriptParser::MatchNode *GDScriptParser::parse_match() {
	MatchNode *match = alloc_node<MatchNode>();
	match->test = parse_expression(false);
	if (match->test == nullptr) {
		push_error(R"(Expected expression to test after "match".)");
	}
	consume(GDScriptTokenizer::Token::COLON, R"(Expected ":" after "match" expression.)");