Fix build with rust 1.94, https://github.com/ulyssa/iamb/issues/598

error[E0275]: overflow evaluating the requirement `{async fn body of matrix_sdk::matrix_sdk_crypto::store::Store::get_sessions()}: std::marker::Send`
     |
     = help: consider increasing the recursion limit by adding a `#![recursion_limit = "256"]` attribute to your crate (`iamb`)
note: required because it appears within the type `impl Future<Output = Result<Option<...>, ...>>`

Index: src/main.rs
--- src/main.rs.orig
+++ src/main.rs
@@ -11,6 +11,7 @@
 //!
 //! Most rendering logic lives under the [windows] module, but [Matrix messages][message] have
 //! their own module.
+#![recursion_limit = "256"]
 #![allow(clippy::manual_range_contains)]
 #![allow(clippy::needless_return)]
 #![allow(clippy::result_large_err)]
