How To: Add merge tags into form description/title

Recently I had a situation where I wanted to use one form on many pages but wanted to include the post title in the form description. For example. Inquire about [SERVICE NAME] that way I could use just one form for all pages but have them appear unique. The solution gform_pre_render Here is the code I used:

add_filter("gform_pre_render", "gf_description_merger");
function gf_description_merger($form) {
        $form['description'] = GFCommon::replace_variables($form['description']);
        return $form;
}

Pastebin

This could most likely be applied to the title and or anywhere else merge tags would like to be used.