### 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
{ nullptr,                                          &GDScriptParser::parse_attribute,            	PREC_ATTRIBUTE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ &GDScriptParser::parse_get_node,               	nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		
		{ &GDScriptParser::parse_builtin_constant,			nullptr,                                        PREC_NONE }, 
		{ &GDScriptParser::parse_builtin_constant,			nullptr,                                        PREC_NONE }, 
		{ &GDScriptParser::parse_builtin_constant,			nullptr,                                        PREC_NONE }, 
		{ &GDScriptParser::parse_builtin_constant,			nullptr,                                        PREC_NONE }, 
		
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          &GDScriptParser::parse_invalid_token,        	PREC_CAST }, 
		
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
		{ nullptr,                                          nullptr,                                        PREC_NONE }, 
	};
	
	
	static_assert(sizeof(rules) / sizeof(rules[0]) == GDScriptTokenizer::Token::TK_MAX, "Amount of parse rules don't match the amount of token types.");
	
	return &rules[p_token_type];
}
bool GDScriptParser::SuiteNode::has_local(const StringName &p_name) const {