truncate FP and use helpers

lib/philomena_web/templates/comment/_comment.html.slime

@@ -27,7 +27,7 @@ article.block.communication id="comment_#{@comment.id}"
           .communication__info
             =<> @comment.ip
           .communication__info
-            =<> @comment.fingerprint
+            =<> link_to_fingerprint(@comment.fingerprint)
     /- if can?(:hide, Comment)
     /  .js-staff-action
     /    - if !comment.hidden_from_users && !comment.destroyed_content

lib/philomena_web/views/comment_view.ex

@@ -1,3 +1,19 @@
 defmodule PhilomenaWeb.CommentView do
   use PhilomenaWeb, :view
+
+  def link_to_ip(ip) do
+    if ip do
+      ip
+    else
+      "N/A"
+    end
+  end
+
+  def link_to_fingerprint(fp) do
+    if fp do
+      fp |> String.slice(0..6)
+    else
+      "N/A"
+    end
+  end
 end