Re-add feature that is still unstable on the build server

src/lib.rs

@@ -18,6 +18,7 @@
 #![feature(unboxed_closures)]
 #![feature(trait_upcasting)]
 #![feature(lazy_cell)]
+#![feature(is_some_and)]
 
 //! PkmnLib
 //! PkmnLib is a full featured implementation of Pokemon. while currently focused on implementing