fix(_parse_{help,usage}): avoid command_not_found_handle

Author: akinomyoga

bash_completion

@@ -1112,7 +1112,7 @@ _parse_help()
     (
         case $cmd in
             -) exec cat ;;
-            *) _comp_dequote "$cmd" && LC_ALL=C "$ret" ${2:---help} 2>&1 ;;
+            *) _comp_dequote "$cmd" && type -- "$ret" &>/dev/null && LC_ALL=C "$ret" ${2:---help} 2>&1 ;;
         esac
     ) |
         while read -r line; do
@@ -1149,7 +1149,7 @@ _parse_usage()
     (
         case $cmd in
             -) exec cat ;;
-            *) _comp_dequote "$cmd" && LC_ALL=C "$ret" ${2:---usage} 2>&1 ;;
+            *) _comp_dequote "$cmd" && type -- "$ret" &>/dev/null && LC_ALL=C "$ret" ${2:---usage} 2>&1 ;;
         esac
     ) |
         while read -r line; do