WIP: Make Vec use count instead of count_with.

I'm not sure of the semver considerations of changing the signature
of count like this is. Does this accept strictly more code, or is
there code that previously would have been accepted that is no
longer accepted?

binrw/src/binread/impls.rs

@@ -143,7 +143,7 @@ where
         endian: Endian,
         args: Self::Args<'_>,
     ) -> BinResult<Self> {
-        crate::helpers::count_with(args.count, B::read_options)(reader, endian, args.inner)
+        crate::helpers::count(args.count)(reader, endian, args.inner)
     }
 }
 

binrw/src/helpers.rs

@@ -445,9 +445,9 @@ where
 /// # let x: CountBytes = x.read_be().unwrap();
 /// # assert_eq!(x.data, &[1, 2, 3]);
 /// ```
-pub fn count<R, T, Arg, Ret>(n: usize) -> impl Fn(&mut R, Endian, Arg) -> BinResult<Ret>
+pub fn count<'a, R, T, Arg, Ret>(n: usize) -> impl Fn(&mut R, Endian, Arg) -> BinResult<Ret>
 where
-    T: for<'a> BinRead<Args<'a> = Arg>,
+    T: BinRead<Args<'a> = Arg>,
     R: Read + Seek,
     Arg: Clone,
     Ret: FromIterator<T> + 'static,