Remove commented out code and a fixed FIXME

The [issue it refers to](rust-lang/rust#15679) was closed a year ago.

Author: tormol

src/ascii_str.rs

@@ -171,15 +171,6 @@ impl PartialEq<AsciiStr> for str {
     }
 }
 
-/*
-impl PartialOrd<AsciiString> for AsciiStr {
-    #[inline]
-    fn partial_cmp(&self, other: &AsciiString) -> Option<Ordering> {
-        self.as_bytes().partial_cmp(other.as_bytes())
-    }
-}
-*/
-
 impl Default for &'static AsciiStr {
     fn default() -> &'static AsciiStr {
         unsafe { mem::transmute("") }

src/lib.rs

@@ -7,8 +7,6 @@
 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
-//
-// ignore-lexer-test FIXME #15679
 
 //! Operations on ASCII strings and characters