Better error report for type in a module

Hej,

It's not really a bug but I don't know where to put this kind of suggestion, please feel free to shout me if you want...

When a type is inside a module, that the file has another name, it is sometimes hard to find the file where the type is.
For example, I get this error : `lib/hscript/git/hscript/Macro.hx:253: characters 38-42 : haxe.macro.Position has no field file`
It's ok here because I know that `haxe.macro.Position` is in `haxe.macro.Expr` file but it's sometimes not evidence.
Maybe it would be better to have `haxe.macro.Expr.Position` instead of `haxe.macro.Position` ?

BTW it's confusing me sometimes because it looks like it"s not really unified between error reporting and import styatement for example, for this example error is `haxe.macro.Position` but if you want to use this type in import so you have to import `haxe.macro.Expr.Position`