lnrpc: undo GetInfo Chains list deprecation

lnrpc/lightning.proto

@@ -1940,10 +1940,11 @@ message GetInfoResponse {
     reserved 11;
 
     /*
-    Deprecated. The only active chain is bitcoin.
-    A list of active chains the node is connected to
+    A list of active chains the node is connected to. This will only
+    ever contain a single entry since LND will only ever have a single
+    chain backend during its lifetime.
     */
-    repeated Chain chains = 16 [deprecated = true];
+    repeated Chain chains = 16;
 
     // The URIs of the current node.
     repeated string uris = 12;

lnrpc/lightning.swagger.json

@@ -5003,7 +5003,7 @@
           "items": {
             "$ref": "#/definitions/lnrpcChain"
           },
-          "title": "Deprecated. The only active chain is bitcoin.\nA list of active chains the node is connected to"
+          "description": "A list of active chains the node is connected to. This will only\never contain a single entry since LND will only ever have a single\nchain backend during its lifetime."
         },
         "uris": {
           "type": "array",