Fix a small typo

Author: HD Moore

modules/auxiliary/scanner/natpmp/natpmp_portscan.rb

@@ -48,7 +48,7 @@ def run_host(host)
       if (external_address)
         print_good("#{peer} responded with external address of #{external_address}")
       else
-        vprint_status("#{peer} didn't responsd with an external address")
+        vprint_status("#{peer} didn't respond with an external address")
         return
       end