fix(cli): fix plugin and theme suggestions in completion for older zsh versions

lib/cli.zsh

@@ -68,10 +68,12 @@ function _omz {
 
         _describe 'plugin' valid_plugins ;;
       plugin::info)
-        local -aU plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(.N:h:t))
+        local -aU plugins
+        plugins=("$ZSH"/plugins/*/{_*,*.plugin.zsh}(.N:h:t) "$ZSH_CUSTOM"/plugins/*/{_*,*.plugin.zsh}(.N:h:t))
         _describe 'plugin' plugins ;;
       theme::(set|use))
-        local -aU themes=("$ZSH"/themes/*.zsh-theme(.N:t:r) "$ZSH_CUSTOM"/**/*.zsh-theme(.N:r:gs:"$ZSH_CUSTOM"/themes/:::gs:"$ZSH_CUSTOM"/:::))
+        local -aU themes
+        themes=("$ZSH"/themes/*.zsh-theme(.N:t:r) "$ZSH_CUSTOM"/**/*.zsh-theme(.N:r:gs:"$ZSH_CUSTOM"/themes/:::gs:"$ZSH_CUSTOM"/:::))
         _describe 'theme' themes ;;
     esac
   elif (( CURRENT > 4 )); then