`::h/for` could support `:index`

[tatut]

If you need an running index number, you usually need to add map-indexed around your data to assoc it.
For could support it automatically by specifying a symbol.

Example of use with this feature:

[:ul 
  [::h/for [{:item/keys [name]} (fetch-my-items db)
            :index i]
    [:li {:class (if (even? i) "eden" "odd)} name]]]