util/IMdkit: Fix typing freeze with barcode reader

After libX11 is fixed about the XIM jumbled input issues, too quick
focus change can causes a freeze with barcode reader.
Seems the modifier key of Alt-Tab effects the input of the barcode
reader but the new issue cannot be reproduced with debug messages.

Hence the new issue could effect the machine spec and timing.
I can avoid the new issue with adding sync() instead of a debug message.
I don't understand the issue fully but hope this fix.

BUG=https://gitlab.freedesktop.org/xorg/lib/libx11/-/issues/198
BUG=#2560

util/IMdkit/i18nPtHdr.c

@@ -1757,6 +1757,7 @@ static void ProcessQueue (XIMS ims, CARD16 connect_id)
         switch (hdr->major_opcode)
         {
         case XIM_FORWARD_EVENT:
+            sync();
             ForwardEventMessageProc(ims, &call_data, p1);
             break;
         }