### 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
ERR_FAIL_COND_V_MSG(p_node->type != Node::VARIABLE, false, vformat(R"("%s" annotation can only be applied to variables.)", p_annotation->name));
	VariableNode *variable = static_cast<VariableNode *>(p_node);
	if (variable->exported) {
		push_error(vformat(R"(Annotation "%s" cannot be used with another "@export" annotation.)", p_annotation->name), p_annotation);
		return false;
	}
	variable->exported = true;
	variable->export_info.type = t_type;
	variable->export_info.hint = t_hint;
	String hint_string;
	for (int i = 0; i < p_annotation->resolved_arguments.size(); i++) {
		String arg_string = String(p_annotation->resolved_arguments[i]);
		if (p_annotation->name != SNAME("@export_placeholder")) {
			if (arg_string.is_empty()) {
				push_error(vformat(R"(Argument %d of annotation "%s" is empty.)", i + 1, p_annotation->name), p_annotation->arguments[i]);
				return false;
			}
			if (arg_string.contains(",")) {
				push_error(vformat(R"(Argument %d of annotation "%s" contains a comma. Use separate arguments instead.)", i + 1, p_annotation->name), p_annotation->arguments[i]);
				return false;
			}
		}
		if (p_annotation->name == SNAME("@export_flags")) {
			const int64_t max_flags = 32;
			Vector<String> t = arg_string.split(":", true, 1);
			if (t[0].is_empty()) {