adjust user contribution calendar time formatting

app/views/users/calendar_activities.html.haml

 %h4.prepend-top-20
   Contributions for
-  %strong= @calendar_date.to_s(:short)
+  %strong= @calendar_date.to_s(:medium)
 
 - if @events.any?
   %ul.bordered-list
@@ -8,7 +8,7 @@
       %li
         %span.light
           %i.fa.fa-clock-o
-          = event.created_at.to_s(:time)
+          = event.created_at.strftime('%-I:%M%P')
         - if event.push?
           #{event.action_name} #{event.ref_type}
           %strong
@@ -30,4 +30,4 @@
             = event.project_name
 - else
   %p
-    No contributions found for #{@calendar_date.to_s(:short)}
+    No contributions found for #{@calendar_date.to_s(:medium)}