replace u8 iterator with slice matching

Author: the8472

library/std/src/path.rs

@@ -729,10 +729,10 @@ impl<'a> Components<'a> {
         if self.has_root() {
             return false;
         }
-        let mut iter = self.path[self.prefix_remaining()..].iter();
-        match (iter.next(), iter.next()) {
-            (Some(&b'.'), None) => true,
-            (Some(&b'.'), Some(&b)) => self.is_sep_byte(b),
+        let slice = &self.path[self.prefix_remaining()..];
+        match slice {
+            [b'.'] => true,
+            [b'.', b, ..] => self.is_sep_byte(*b),
             _ => false,
         }
     }