mini-macro: fix build with latest rustc (rename feature: proc_macro_non_items -> proc_macro_hygiene).

Author: matthiaskrgr

mini-macro/src/lib.rs

@@ -1,4 +1,4 @@
-#![feature(proc_macro_quote, proc_macro_non_items)]
+#![feature(proc_macro_quote, proc_macro_hygiene)]
 extern crate proc_macro;
 
 use proc_macro::{TokenStream, quote};
@@ -8,4 +8,4 @@ pub fn mini_macro(_: TokenStream) -> TokenStream {
     quote!(
         #[allow(unused)] fn needless_take_by_value(s: String) { println!("{}", s.len()); }
     )
-}
+}