docs(chain): fix docs

crates/chain/src/keychain/txout_index.rs

@@ -29,9 +29,9 @@ pub const DEFAULT_LOOKAHEAD: u32 = 25;
 /// and only one descriptor and each descriptor has one and only one keychain. The
 /// [`insert_descriptor`] method will return an error if you try and violate this invariant. This
 /// rule is a proxy for a stronger rule: no two descriptors should produce the same script pubkey.
-/// Having two descriptors produce the same script pubkey should cause whichever keychain derives the
-/// script pubkey first to be the effective owner of it but you should not rely on this behaviour.
-/// ⚠ It is up you, the developer, not to violate this invariant.
+/// Having two descriptors produce the same script pubkey should cause whichever keychain derives
+/// the script pubkey first to be the effective owner of it but you should not rely on this
+/// behaviour. ⚠ It is up you, the developer, not to violate this invariant.
 ///
 /// # Revealed script pubkeys
 ///
@@ -341,7 +341,7 @@ impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
 }
 
 impl<K: Clone + Ord + Debug> KeychainTxOutIndex<K> {
-    /// Return the map of the keychain to descriptors.
+    /// Return all keychains and their corresponding descriptors.
     pub fn keychains(
         &self,
     ) -> impl DoubleEndedIterator<Item = (&K, &Descriptor<DescriptorPublicKey>)> + ExactSizeIterator + '_