make feature requirement render in rustdoc for new apis

crates/wasmtime/src/externals.rs

@@ -444,6 +444,7 @@ impl Table {
         Table::_new(store.as_context_mut().0, ty, init)
     }
 
+    #[cfg_attr(nightlydoc, doc(cfg(feature = "async")))]
     /// Async variant of [`Table::new`]. You must use this variant with
     /// [`Store`](`crate::Store`)s which have a
     /// [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`).
@@ -603,6 +604,7 @@ impl Table {
         }
     }
 
+    #[cfg_attr(nightlydoc, doc(cfg(feature = "async")))]
     /// Async variant of [`Table::grow`]. Required when using a
     /// [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`).
     ///

crates/wasmtime/src/memory.rs

@@ -230,6 +230,7 @@ impl Memory {
         Memory::_new(store.as_context_mut().0, ty)
     }
 
+    #[cfg_attr(nightlydoc, doc(cfg(feature = "async")))]
     /// Async variant of [`Memory::new`]. You must use this variant with
     /// [`Store`](`crate::Store`)s which have a
     /// [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`).
@@ -508,6 +509,7 @@ impl Memory {
         }
     }
 
+    #[cfg_attr(nightlydoc, doc(cfg(feature = "async")))]
     /// Async variant of [`Memory::grow`]. Required when using a
     /// [`ResourceLimiterAsync`](`crate::ResourceLimiterAsync`).
     ///

crates/wasmtime/src/store.rs

@@ -533,6 +533,7 @@ impl<T> Store<T> {
         inner.limiter = Some(ResourceLimiterInner::Sync(Box::new(limiter)));
     }
 
+    #[cfg_attr(nightlydoc, doc(cfg(feature = "async")))]
     /// Configures the [`ResourceLimiterAsync`](crate::ResourceLimiterAsync)
     /// used to limit resource creation within this [`Store`]. Must be used
     /// with an async `Store`!.