Allow doc comments to be terminated with EOF

Closes #61
diff --git a/src/stable.rs b/src/stable.rs
index ffa077a..41a7c4b 100644
--- a/src/stable.rs
+++ b/src/stable.rs
@@ -1179,7 +1179,7 @@
 named!(doc_comment -> (), alt!(
     do_parse!(
         punct!("//!") >>
-        take_until!("\n") >>
+        take_until_newline_or_eof!() >>
         (())
     )
     |
@@ -1193,7 +1193,7 @@
     do_parse!(
         punct!("///") >>
         not!(tag!("/")) >>
-        take_until!("\n") >>
+        take_until_newline_or_eof!() >>
         (())
     )
     |