fix(codegen): use full path for std types (#1702)

* nit: rename macro file

* nit: naming & docs

* fix(codegen): use full path for std Result

* fix: same for Vec, remove next tests

* nit: formatting

* fix: vec path

* nit: bullet proof names

* nit: comments, naming, ordering of tests

* ::

* fix: output names

Author: jonaro00

codegen/src/lib.rs

@@ -55,5 +55,5 @@ pub fn main(
     attr: proc_macro::TokenStream,
     item: proc_macro::TokenStream,
 ) -> proc_macro::TokenStream {
-    shuttle_main::r#impl(attr, item)
+    shuttle_main::tokens(attr, item)
 }