Fix malformed-HTML fallout across RSS, link rewriting, and flash messaging

Editors' TinyMCE output can contain unclosed void elements like <br>,
which is valid HTML5 but invalid XML -- three different places assumed
the stricter rule and broke or silently misbehaved on the looser one.
The Atom feed's <content type="xhtml"> block required real, well-formed
XML structure but was handed a raw, unescaped body string; switched to
type="html" with CGI.escapeHTML, matching how title/summary already
handle the same content. rewrite_links_in_body used libxml's strict XML
parser to rewrite internal links to be locale-prefixed, which raised on
exactly this class of malformed markup -- silently, since the whole
method was wrapped in rescue; nil, meaning the link rewrite (not the
save) quietly failed with no error anywhere. Replaced with Nokogiri's
lenient HTML parser, which repairs malformed void elements rather than
rejecting them; also drops the bare rescue now that the actual failure
mode it was guarding against shouldn't occur, and fixes two adjacent
bugs found while in this method: a typo'd /sytem/uploads/ regex that
could never match, and a missing https:// exclusion alongside the
existing http:// one.

Also addresses stale flash messaging surfaced while testing the above:
update's save confirmation was being clobbered by edit's own "locked
and ready" notice on the very next request, since nothing distinguished
a fresh lock acquisition from a redirect back after saving. The save
confirmation now names the next step (publish from Status) and flags a
stale translation if one exists, using Page#outdated_translations?,
already present but previously unused by any controller.

1 files changed, 7 insertions, 0 deletions

diff --git a/app/views/layouts/admin.html.erb b/app/views/layouts/admin.html.erb
index 340eaf2..79b1380 100644
--- a/app/views/layouts/admin.html.erb
+++ b/app/views/layouts/admin.html.erb
@@ -33,6 +33,13 @@
       <% if flash[:notice].present? || flash[:error].present? %>
       <div id="flash">
         <%= flash[:notice] %>
+        <% if flash[:status_path] %>
+          <%= link_to 'Go to Status', flash[:status_path] %>
+        <% end %>
+        <% if flash[:stale_locale_path] %>
+          The <%= flash[:stale_locale] %> translation may be out of date —
+          <%= link_to 'review it', flash[:stale_locale_path] %> too.
+        <% end %>
         <% if flash[:error] %>
           <span id="flash_error"><%= flash[:error] %></span>
         <% end %>