rpc: fix getpeerinfo ping duration unit docs

The getpeerinfo docs incorrectly specified the ping durations as
milliseconds. This was incorrectly changed in a3789c7
(released in v25; master since Sept. 2022). The correct duration unit
is seconds.

Also, remove the documentation of the getpeerinfo RPC response from the
ping RPC since it's incomplete. Better to just reference the getpeerinfo
RPC and it's documenation for this.

Author: 0xB10C

src/rpc/net.cpp

@@ -85,7 +85,7 @@ static RPCHelpMan ping()
     return RPCHelpMan{
         "ping",
         "Requests that a ping be sent to all other nodes, to measure ping time.\n"
-                "Results provided in getpeerinfo, pingtime and pingwait fields are decimal seconds.\n"
+                "Results are provided in getpeerinfo.\n"
                 "Ping command is handled in queue with all other commands, so it measures processing backlog, not just network ping.\n",
                 {},
                 RPCResult{RPCResult::Type::NONE, "", ""},
@@ -150,9 +150,9 @@ static RPCHelpMan getpeerinfo()
                     {RPCResult::Type::NUM, "bytesrecv", "The total bytes received"},
                     {RPCResult::Type::NUM_TIME, "conntime", "The " + UNIX_EPOCH_TIME + " of the connection"},
                     {RPCResult::Type::NUM, "timeoffset", "The time offset in seconds"},
-                    {RPCResult::Type::NUM, "pingtime", /*optional=*/true, "The last ping time in milliseconds (ms), if any"},
-                    {RPCResult::Type::NUM, "minping", /*optional=*/true, "The minimum observed ping time in milliseconds (ms), if any"},
-                    {RPCResult::Type::NUM, "pingwait", /*optional=*/true, "The duration in milliseconds (ms) of an outstanding ping (if non-zero)"},
+                    {RPCResult::Type::NUM, "pingtime", /*optional=*/true, "The last ping time in seconds, if any"},
+                    {RPCResult::Type::NUM, "minping", /*optional=*/true, "The minimum observed ping time in seconds, if any"},
+                    {RPCResult::Type::NUM, "pingwait", /*optional=*/true, "The duration in seconds of an outstanding ping (if non-zero)"},
                     {RPCResult::Type::NUM, "version", "The peer version, such as 70001"},
                     {RPCResult::Type::STR, "subver", "The string version"},
                     {RPCResult::Type::BOOL, "inbound", "Inbound (true) or Outbound (false)"},