Change default TokenModifiers global color

[comedinha]

In the vscode, these is the standard tokens defined: https://code.visualstudio.com/api/language-extensions/semantic-highlight-guide#standard-token-types-and-modifiers Doen't exist a "variable.global" token to TokenModifiers, and "variable.static" token was removed in https://github.com/LuaLS/lua-language-server/issues/1458 this modification makes the global variable become the same color as local variable if it isn't is configured. This forces everyone to need to go configure manually.

So I think is better to use some standard token to the themes automatically color globals and locals variables. My suggestion is use the token "variable.definition" or "variable.readonly".

"variable.definition" is used in self, so if it will be accepted the suggestion is change self to "variable.static" or "variable.readonly"