f update docs about fallibility on reading monitors

lightning/src/util/persist.rs

@@ -333,11 +333,11 @@ where
 /// ## EXTREMELY IMPORTANT
 /// 
 /// It is extremely important that your [`KVStore::read`] implementation uses the
-/// [`io::ErrorKind::NotFound`] variant correctly: that is, when a file is not found, and _only_
-/// in that circumstance (not when there is really a permissions error, for example). This is
-/// because this function does not list updates. Instead, it reads the monitor, and using its
-/// stored `update_id`, synthesizes update storage keys, and tries them in sequence until one is
-/// not found. All _other_ errors will be bubbled up in this function's [`io::Result`].
+/// [`io::ErrorKind::NotFound`] variant correctly: that is, when a file is not found, and _only_ in
+/// that circumstance (not when there is really a permissions error, for example). This is because
+/// neither channel monitor reading function lists updates. Instead, either reads the monitor, and
+/// using its stored `update_id`, synthesizes update storage keys, and tries them in sequence until
+/// one is not found. All _other_ errors will be bubbled up in the function's [`Result`].
 ///
 /// # Pruning stale channel updates
 ///