hmp: rename arguments

Rename 'string' to 'keys', rename 'hold_time' to 'hold-time'.

Signed-off-by: Amos Kong <[email protected]>
Signed-off-by: Luiz Capitulino <[email protected]>
diff --git a/hmp-commands.hx b/hmp-commands.hx
index 6a70a9c..bd0c6c9 100644
--- a/hmp-commands.hx
+++ b/hmp-commands.hx
@@ -502,7 +502,7 @@
 
     {
         .name       = "sendkey",
-        .args_type  = "string:s,hold_time:i?",
+        .args_type  = "keys:s,hold-time:i?",
         .params     = "keys [hold_ms]",
         .help       = "send keys to the VM (e.g. 'sendkey ctrl-alt-f1', default hold time=100 ms)",
         .mhandler.cmd = do_sendkey,