add nft_page (#637)

Fixes #638

src/rpc/handlers/LedgerEntry.cpp

@@ -189,6 +189,7 @@ tag_invoke(boost::json::value_to_tag<LedgerEntryHandler::Input>, boost::json::va
         {JS(payment_channel), ripple::ltPAYCHAN},
         {JS(deposit_preauth), ripple::ltDEPOSIT_PREAUTH},
         {JS(ticket), ripple::ltTICKET},
+        {JS(nft_page), ripple::ltNFTOKEN_PAGE},
     };
 
     auto const indexFieldType =

src/rpc/handlers/LedgerEntry.h

@@ -28,7 +28,6 @@ namespace RPC {
 
 /**
  * @brief The ledger_entry method returns a single ledger object from the XRP Ledger in its raw format.
- * The clio has not supported: nft_page
  *
  * For more details see: https://xrpl.org/ledger_entry.html
  */
@@ -47,7 +46,6 @@ public:
         bool validated = true;
     };
 
-    // TODO: nft_page has not been implemented
     struct Input
     {
         std::optional<std::string> ledgerHash;
@@ -156,6 +154,7 @@ public:
                      {JS(ticket_seq), validation::Required{}, validation::Type<uint32_t>{}},
                  },
              }},
+            {JS(nft_page), validation::Uint256HexStringValidator},
         };
 
         return rpcSpec;