libfmt_macros: Remove all uses of ~str from libfmt_macros

src/libfmt_macros/lib.rs

@@ -203,7 +203,7 @@ pub struct Parser<'a> {
     cur: str::CharOffsets<'a>,
     depth: uint,
     /// Error messages accumulated during parsing
-    pub errors: Vec<~str>,
+    pub errors: Vec<StrBuf>,
 }
 
 impl<'a> Iterator<Piece<'a>> for Parser<'a> {
@@ -246,10 +246,10 @@ impl<'a> Parser<'a> {
     }
 
     /// Notifies of an error. The message doesn't actually need to be of type
-    /// ~str, but I think it does when this eventually uses conditions so it
+    /// StrBuf, but I think it does when this eventually uses conditions so it
     /// might as well start using it now.
     fn err(&mut self, msg: &str) {
-        self.errors.push(msg.to_owned());
+        self.errors.push(msg.to_strbuf());
     }
 
     /// Optionally consumes the specified character. If the character is not at