only use #[no_core] in libcore

src/librustdoc/text_pass.rs

@@ -10,8 +10,6 @@
 
 //! Generic pass for performing an operation on all descriptions
 
-use core::prelude::*;
-
 use astsrv;
 use doc::ItemUtils;
 use doc;
@@ -147,8 +145,6 @@ mod test {
     use sectionalize_pass;
     use text_pass::mk_pass;
 
-    use core::prelude::*;
-
     fn mk_doc(source: ~str) -> doc::Doc {
         do astsrv::from_str(copy source) |srv| {
             let doc = extract::from_srv(srv.clone(), ~"");