rpc: doc: mention rescan speedup using blockfilterindex=1 in affected wallet RPCs

Author: theStack

src/wallet/rpc/backup.cpp

@@ -1589,7 +1589,8 @@ RPCHelpMan importdescriptors()
     return RPCHelpMan{"importdescriptors",
                 "\nImport descriptors. This will trigger a rescan of the blockchain based on the earliest timestamp of all descriptors being imported. Requires a new wallet backup.\n"
             "\nNote: This call can take over an hour to complete if using an early timestamp; during that time, other rpc calls\n"
-            "may report that the imported keys, addresses or scripts exist but related transactions are still missing.\n",
+            "may report that the imported keys, addresses or scripts exist but related transactions are still missing.\n"
+            "The rescan is significantly faster if block filters are available (using startup option \"-blockfilterindex=1\").\n",
                 {
                     {"requests", RPCArg::Type::ARR, RPCArg::Optional::NO, "Data to be imported",
                         {
@@ -1887,7 +1888,9 @@ RPCHelpMan restorewallet()
 {
     return RPCHelpMan{
         "restorewallet",
-        "\nRestore and loads a wallet from backup.\n",
+        "\nRestore and loads a wallet from backup.\n"
+        "\nThe rescan is significantly faster if a descriptor wallet is restored"
+        "\nand block filters are available (using startup option \"-blockfilterindex=1\").\n",
         {
             {"wallet_name", RPCArg::Type::STR, RPCArg::Optional::NO, "The name that will be applied to the restored wallet"},
             {"backup_file", RPCArg::Type::STR, RPCArg::Optional::NO, "The backup file that will be used to restore the wallet."},

src/wallet/rpc/transactions.cpp

@@ -839,7 +839,9 @@ RPCHelpMan rescanblockchain()
 {
     return RPCHelpMan{"rescanblockchain",
                 "\nRescan the local blockchain for wallet related transactions.\n"
-                "Note: Use \"getwalletinfo\" to query the scanning progress.\n",
+                "Note: Use \"getwalletinfo\" to query the scanning progress.\n"
+                "The rescan is significantly faster when used on a descriptor wallet\n"
+                "and block filters are available (using startup option \"-blockfilterindex=1\").\n",
                 {
                     {"start_height", RPCArg::Type::NUM, RPCArg::Default{0}, "block height where the rescan should start"},
                     {"stop_height", RPCArg::Type::NUM, RPCArg::Optional::OMITTED_NAMED_ARG, "the last block height that should be scanned. If none is provided it will rescan up to the tip at return time of this call."},