SATS derive(Deserialize) fails for empty enums

[gefjon]

#[derive(Deserialize)]
enum Empty {}

Fails with an error like:

error[E0283]: type annotations needed
   --> crates/sdk/tests/connect_disconnect_client/src/module_bindings/mod.rs:28:21
    |
28  | #[derive(Serialize, Deserialize, Clone, PartialEq, Debug)]
    |                     ^^^^^^^^^^^ cannot infer type
    |
    = note: cannot satisfy `_: AsRef<str>`
note: required by a bound in `<dyn ValidNames>::extend`
   --> /home/phoebe/clockworklabs/SpacetimeDB/crates/sats/src/de.rs:406:18
    |
404 |     pub fn extend<I: IntoIterator>(&mut self, iter: I)
    |            ------ required by a bound in this associated function
405 |     where
406 |         I::Item: AsRef<str>,
    |                  ^^^^^^^^^^ required by this bound in `<dyn ValidNames>::extend`
    = note: this error originates in the derive macro `Deserialize` (in Nightly builds, run with -Z macro-backtrace for more info)

For more information about this error, try `rustc --explain E0283`.
error: could not compile `connect_disconnect_client` (bin "connect_disconnect_client") due to previous error

This makes it impossible to compile autogenerated module_bindings for a module which defines no reducers.