### 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
if (key == nullptr) {
						push_error(R"(Expected expression as key for dictionary pattern.)");
					}
					if (match(GDScriptTokenizer::Token::COLON)) {
						
						PatternNode *sub_pattern = parse_match_pattern(p_root_pattern != nullptr ? p_root_pattern : pattern);
						if (sub_pattern == nullptr) {
							continue;
						}
						if (pattern->rest_used) {
							push_error(R"(The ".." pattern must be the last element in the pattern dictionary.)");
						} else if (sub_pattern->pattern_type == PatternNode::PT_REST) {
							push_error(R"(The ".." pattern cannot be used as a value.)");
						} else {
							pattern->dictionary.push_back({ key, sub_pattern });
						}
					} else {
						
						pattern->dictionary.push_back({ key, nullptr });
					}
				}
			} while (match(GDScriptTokenizer::Token::COMMA));
			consume(GDScriptTokenizer::Token::BRACE_CLOSE, R"(Expected "}" to close the dictionary pattern.)");
			break;
		}
		default: {
			
			ExpressionNode *expression = parse_expression(false);
			if (expression == nullptr) {
				push_error(R"(Expected expression for match pattern.)");