multi: fix typos in comments

lnwallet/README.md

@@ -13,7 +13,7 @@ derivation, and the commitment update state machine.
 The package is used within `lnd` as the core wallet of the daemon. The wallet
 itself is composed of several distinct interfaces that decouple the
 implementation of things like signing and blockchain access. This separation
-allows new `WalletController` implementations to be be easily dropped into
+allows new `WalletController` implementations to be easily dropped into
 `lnd` without disrupting the code base. A series of integration tests at the
 interface level are also in place to ensure conformance of the implementation
 with the interface.