Ensure compinit updates its modified date

`compinit -i` doesn't always change zcompdump, which means that the
`compinit -C` condition fails to run until the completions change.
When we `compinit -i`, we should touch the file too to solve this.

modules/completion/init.zsh

@@ -40,6 +40,7 @@ if [[ $_comp_path(#qNmh-20) ]]; then
 else
   mkdir -p "$_comp_path:h"
   compinit -i -d "$_comp_path"
+  touch "$_comp_path"
 fi
 unset _comp_path