fix(complete): remove empty elements

Author: akinomyoga

completions/complete

@@ -40,7 +40,7 @@ _comp_cmd_complete()
         local -a opts=($(compgen -W '$(_parse_usage help "-s $1")' -- "$cur"))
         # -F, -C do not work the expected way with compgen
         [[ $1 != *compgen ]] || opts=("${opts[@]//-[FC]/}")
-        COMPREPLY=($(compgen -W '"${opts[@]}"' -- "$cur"))
+        COMPREPLY=($(compgen -W '"${opts[@]}"' -X '' -- "$cur"))
     else
         COMPREPLY=($(compgen -A command -- "$cur"))
     fi