complete the feature for the cover dimming class in page

- feature already present for site
- add info for the param to the example

Signed-off-by: Patrick Kollitsch <patrick@davids-neighbour.com>

exampleSite/config.toml

@@ -38,6 +38,8 @@ description = "The last theme you'll ever need. Maybe."
 background_color_class = "bg-black"
 # choose an fitting and alignment style for the featured image using tachyons classes such as "cover|contain" for fitting and "bg-top|bg-center|bg-bottom" for alignment, or add any other class space-separated to customize further
 featured_image_class = "cover bg-top"
+# choose a color dimming class for the page or size header from any on this page: https://tachyons.io/docs/themes/skins/, preface it with "bg-" and add the value such as "-X0" where X is in [1,9]
+cover_dimming_class = "bg-black-60"
 recent_posts_number = 3
 
 [ananke.social.follow]

layouts/partials/page-header.html

@@ -2,7 +2,7 @@
 {{ if $featured_image }}
   {{/* Trimming the slash and adding absURL make sure the image works no matter where our site lives */}}
   <header class="{{ .Params.featured_image_class | .Site.Params.featured_image_class | default "cover bg-top" }}" style="background-image: url('{{ $featured_image }}');">
-    <div class="bg-black-60">
+    <div class="{{ .Params.cover_dimming_class | .Site.Params.cover_dimming_class | default "bg-black-60" }}">
       {{ partial "site-navigation.html" . }}
       <div class="tc-l pv6 ph3 ph4-ns">
         {{ if not .Params.omit_header_text }}