Use non-binary pronouns in comments. (#13209)

* use non binary pronouns in comments

* cargo fmt

* fix the use of "it" with "they" when dealing about an opperations identity

substrate/frame/nfts/src/features/transfer.rs

@@ -64,7 +64,7 @@ impl<T: Config<I>, I: 'static> Pallet<T, I> {
 		details.owner = dest;
 
 		// The approved accounts have to be reset to None, because otherwise pre-approve attack
-		// would be possible, where the owner can approve his second account before making the
+		// would be possible, where the owner can approve their second account before making the
 		// transaction and then claiming the item back.
 		details.approvals.clear();