Remove unused argument on CheckedHrpstring::fe32_iter

This is Steven's work in the now very old #220.

Its a one line change so just pick it up and push it in.

FTR no one knows how or why this is here. Its probably my fault ...

Author: tcharding

src/primitives/decode.rs

@@ -444,7 +444,7 @@ impl<'s> CheckedHrpstring<'s> {
     ///
     /// Converts the ASCII bytes representing field elements to the respective field elements.
     #[inline]
-    pub fn fe32_iter(&self, _: u8) -> AsciiToFe32Iter<'_> {
+    pub fn fe32_iter(&self) -> AsciiToFe32Iter<'_> {
         AsciiToFe32Iter { iter: self.ascii.iter().copied() }
     }