serialize/value: Allow Box<str> serialization

We already had an SerializeValue impl for Box<T>, and for &str. The
problem is that Box<str>, as you can see, contains str instead of &str,
so the Box SerializeValue impl could not use that.

Author: Lorak-mmk

scylla-cql/src/serialize/value.rs

@@ -294,7 +294,7 @@ impl SerializeValue for num_bigint_04::BigInt {
             .map_err(|_| mk_ser_err::<Self>(typ, BuiltinSerializationErrorKind::SizeOverflow))?
     });
 }
-impl SerializeValue for &str {
+impl SerializeValue for str {
     impl_serialize_via_writer!(|me, typ, writer| {
         exact_type_check!(typ, Ascii, Text);
         writer
@@ -1066,7 +1066,7 @@ pub struct BuiltinTypeCheckError {
     pub kind: BuiltinTypeCheckErrorKind,
 }
 
-fn mk_typck_err<T>(
+fn mk_typck_err<T: ?Sized>(
     got: &ColumnType,
     kind: impl Into<BuiltinTypeCheckErrorKind>,
 ) -> SerializationError {
@@ -1099,7 +1099,7 @@ pub struct BuiltinSerializationError {
     pub kind: BuiltinSerializationErrorKind,
 }
 
-pub(crate) fn mk_ser_err<T>(
+pub(crate) fn mk_ser_err<T: ?Sized>(
     got: &ColumnType,
     kind: impl Into<BuiltinSerializationErrorKind>,
 ) -> SerializationError {