Add comments for all wallet states [skip ci]

lnrpc/stateservice.swagger.json

@@ -100,7 +100,7 @@
         "WAITING_TO_START"
       ],
       "default": "NON_EXISTING",
-      "description": " - SERVER_ACTIVE: SERVER_ACTIVE means that the lnd server is ready to accept calls."
+      "description": " - NON_EXISTING: NON_EXISTING means that the wallet has not yet been initialized.\n - LOCKED: LOCKED means that the wallet is locked and requires a password to unlock.\n - UNLOCKED: UNLOCKED means that the wallet was unlocked successfully, but RPC server\nisn't ready.\n - RPC_ACTIVE: RPC_ACTIVE means that the lnd server is active but not fully ready for\ncalls.\n - SERVER_ACTIVE: SERVER_ACTIVE means that the lnd server is ready to accept calls.\n - WAITING_TO_START: WAITING_TO_START means that node is waiting to become the leader in a\ncluster and is not started yet."
     },
     "protobufAny": {
       "type": "object",