Remove out-of-date comment.

Author: nnethercote

compiler/rustc_infer/src/infer/resolve.rs

@@ -121,8 +121,6 @@ where
  value.try_fold_with(&mutFullTypeResolver{ infcx })
 }
 
-// N.B. This type is not public because the protocol around checking the
-// `err` field is not enforceable otherwise.
 structFullTypeResolver<'a,'tcx>{
 infcx:&'aInferCtxt<'tcx>,
 }