footer: Reorganize the aria-label translations

* Moves aria-label translation strings of the footer
  into a separate sub-category in `locales/footer.en.yml`,
  allowing the individual translation key names to be much shorter.
  'refuge-restrooms-on-twitter-aria-label'
  => 'aria-labels.refuge-restrooms-on-twitter"

* Shorten the key names further from e.g.:
  'refuge-restrooms-on-twitter' => 'twitter'

* Updates `_footer.html.haml` to use the new key names.

  Thanks again @tkwidmer for the review.

app/views/layouts/_footer.html.haml

@@ -1,14 +1,14 @@
 %footer
   .footer
-    %a.iconLink{:href => "https://github.com/RefugeRestrooms/refugerestrooms", :aria => { :label => t('.refuge-restrooms-on-github-aria-label')}}
+    %a.iconLink{:href => "https://github.com/RefugeRestrooms/refugerestrooms", :aria => { :label => t('.aria-labels.github')}}
       %i.icon.fa.fa-github-square.fa-3x
-    %a.iconLink{:href => "https://twitter.com/refugerestrooms", :aria => { :label => t('.refuge-restrooms-on-twitter-aria-label')}}
+    %a.iconLink{:href => "https://twitter.com/refugerestrooms", :aria => { :label => t('.aria-labels.twitter')}}
       %i.icon.fa.fa-twitter-square.fa-3x
-    %a.iconLink{:href => "https://www.facebook.com/refugerestrooms", :aria => { :label => t('.refuge-restrooms-on-facebook-aria-label')}}
+    %a.iconLink{:href => "https://www.facebook.com/refugerestrooms", :aria => { :label => t('.aria-labels.facebook')}}
       %i.icon.fa.fa-facebook-square.fa-3x
-    %a.iconLink{:href => "http://blog.refugerestrooms.org/", :aria => { :label => t('.refuge-restrooms-blog-on-tumblr-aria-label')}}
+    %a.iconLink{:href => "http://blog.refugerestrooms.org/", :aria => { :label => t('.aria-labels.tumblr')}}
       %i.icon.fa.fa-tumblr-square.fa-3x
-    %a.iconLink{:href => contact_path, :aria => { :label => t('.email-refuge-restrooms-aria-label')}}
+    %a.iconLink{:href => contact_path, :aria => { :label => t('.aria-labels.email')}}
       %i.icon.fa.fa-envelope.fa-3x
     %br/
     = t('.refuge-restrooms-is-open-source')

config/locales/footer.en.yml

@@ -1,11 +1,12 @@
 en:
   layouts:
     footer:
-      refuge-restrooms-on-github-aria-label: 'Refuge Restrooms on GitHub'
-      refuge-restrooms-on-twitter-aria-label: 'Refuge Restrooms on twitter'
-      refuge-restrooms-on-facebook-aria-label: 'Refuge Restrooms on Facebook'
-      refuge-restrooms-blog-on-tumblr-aria-label: 'Refuge Restrooms blog on tumblr'
-      email-refuge-restrooms-aria-label: 'Email Refuge Restrooms'
+      aria-labels:
+        github: 'Refuge Restrooms on GitHub'
+        twitter: 'Refuge Restrooms on twitter'
+        facebook: 'Refuge Restrooms on Facebook'
+        tumblr: 'Refuge Restrooms blog on tumblr'
+        email: 'Email Refuge Restrooms'
       refuge-restrooms-is-open-source: 'refuge restrooms is open source.'
       code-on-github: 'code on github.'
       contribute-to-the-project: 'contribute to the project'