mail-rcpt.d: fix short-text description

docs/cmdline-opts/mail-rcpt.d

@@ -1,6 +1,6 @@
 Long: mail-rcpt
 Arg: <address>
-Help: Mail from this address
+Help: Mail to this address
 Protocols: SMTP
 Added: 7.20.0
 ---

src/tool_help.c

@@ -217,7 +217,7 @@ static const struct helptxt helptext[] = {
   {"    --mail-from <address>",
    "Mail from this address"},
   {"    --mail-rcpt <address>",
-   "Mail from this address"},
+   "Mail to this address"},
   {"-M, --manual",
    "Display the full manual"},
   {"    --max-filesize <bytes>",