I wanna declare a macro that can rewrite variable declaration, named `tonim`,
which can transform\:
● `a: Final = 1` -\> `let a = 1`
● `a = 1` -\> `var a = 1`

And in which it shall be aware of type alias/template, e.g. if given `type
RtConst = Final` ahead, `a: RtConst = 1` also works.