### 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
permission_args++;
				rpc_config["rpc_mode"] = MultiplayerAPI::RPC_MODE_ANY_PEER;
			} else if (arg == "authority") {
				permission_args++;
				rpc_config["rpc_mode"] = MultiplayerAPI::RPC_MODE_AUTHORITY;
			} else if (arg == "reliable") {
				transfer_mode_args++;
				rpc_config["transfer_mode"] = MultiplayerPeer::TRANSFER_MODE_RELIABLE;
			} else if (arg == "unreliable") {
				transfer_mode_args++;
				rpc_config["transfer_mode"] = MultiplayerPeer::TRANSFER_MODE_UNRELIABLE;
			} else if (arg == "unreliable_ordered") {
				transfer_mode_args++;
				rpc_config["transfer_mode"] = MultiplayerPeer::TRANSFER_MODE_UNRELIABLE_ORDERED;
			} else {
				push_error(R"(Invalid RPC argument. Must be one of: "call_local"/"call_remote" (local calls), "any_peer"/"authority" (permission), "reliable"/"unreliable"/"unreliable_ordered" (transfer mode).)", p_annotation);
			}
		}
		if (locality_args > 1) {
			push_error(R"(Invalid RPC config. The locality ("call_local"/"call_remote") must be specified no more than once.)", p_annotation);
		} else if (permission_args > 1) {
			push_error(R"(Invalid RPC config. The permission ("any_peer"/"authority") must be specified no more than once.)", p_annotation);
		} else if (transfer_mode_args > 1) {
			push_error(R"(Invalid RPC config. The transfer mode ("reliable"/"unreliable"/"unreliable_ordered") must be specified no more than once.)", p_annotation);
		}
	}
	function->rpc_config = rpc_config;
	return true;
}
bool GDScriptParser::static_unload_annotation(const AnnotationNode *p_annotation, Node *p_target) {