src: remove TODO about uv errno removal

This commit removes a TODO regarding the removal of uv errno. errno
is currently used and cannot be removed so removing the comment to
avoid any confusion.

PR-URL: nodejs#12536
Ref: nodejs#4641
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Anna Henningsen <anna@addaleax.net>
Reviewed-By: James M Snell <jasnell@gmail.com>

src/node.cc

@@ -940,8 +940,6 @@ Local<Value> UVException(Isolate* isolate,
 
   Local<Object> e = Exception::Error(js_msg)->ToObject(isolate);
 
-  // TODO(piscisaureus) errno should probably go; the user has no way of
-  // knowing which uv errno value maps to which error.
   e->Set(env->errno_string(), Integer::New(isolate, errorno));
   e->Set(env->code_string(), js_code);
   e->Set(env->syscall_string(), js_syscall);