Fix zsh autocompletion. Closes #47.

completions/rbenv.zsh

@@ -1,18 +1,17 @@
-#compdef _rbenv rbenv
+compctl -K _rbenv rbenv
 
 function _rbenv_commands() {
   cmds_str="$(rbenv commands)"
-  cmds=("${(ps:\n:)cmds_str}")
-  _describe '_rbenv_commands' cmds
+  reply=("${(ps:\n:)cmds_str}")
 }
 
 _rbenv_versions() {
   versions_str="$(rbenv versions --bare)"
-  versions=(system "${(ps:\n:)versions_str}")
-  _describe '_rbenv_versions' versions
+  reply=(system "${(ps:\n:)versions_str}")
 }
 
 _rbenv() {
+  read -cA words
   case "$words[2]" in
     set-* | global | local | shell | prefix ) _rbenv_versions ;;
     * ) _rbenv_commands ;;