### 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
MatchBranchNode *branch = alloc_node<MatchBranchNode>();
	reset_extents(branch, current);
	bool has_bind = false;
	do {
		PatternNode *pattern = parse_match_pattern();
		if (pattern == nullptr) {
			continue;
		}
		if (pattern->binds.size() > 0) {
			has_bind = true;
		}
		if (branch->patterns.size() > 0 && has_bind) {
			push_error(R"(Cannot use a variable bind with multiple patterns.)");
		}
		if (pattern->pattern_type == PatternNode::PT_REST) {
			push_error(R"(Rest pattern can only be used inside array and dictionary patterns.)");
		} else if (pattern->pattern_type == PatternNode::PT_BIND || pattern->pattern_type == PatternNode::PT_WILDCARD) {
			branch->has_wildcard = true;
		}
		branch->patterns.push_back(pattern);
	} while (match(GDScriptTokenizer::Token::COMMA));
	if (branch->patterns.is_empty()) {
		push_error(R"(No pattern found for "match" branch.)");
	}
	if (!consume(GDScriptTokenizer::Token::COLON, R"(Expected ":" after "match" patterns.)")) {
		complete_extents(branch);
		return nullptr;
	}
	SuiteNode *suite = alloc_node<SuiteNode>();
	if (branch->patterns.size() > 0) {