Hide unsaved changes warning after undoing them

This way showing the warning is consistent with warning users when
they're leaving the page.

app/assets/javascripts/markdown_editor.js

@@ -22,8 +22,18 @@
         });
         editor = $(this);
         editor.on("input", function() {
+          var textarea, warning;
+
+          textarea = editor.find("textarea")[0];
+          warning = $(this).closest(".translatable-fields").find(".warning");
+
           App.MarkdownEditor.refresh_preview($(this), md);
-          $(".legislation-draft-versions-edit .warning").show();
+
+          if (textarea.value === textarea.defaultValue) {
+            warning.hide();
+          } else {
+            warning.show();
+          }
         });
         editor.find("textarea").on("scroll", function() {
           editor.find(".markdown-preview").scrollTop($(this).scrollTop());

app/views/admin/legislation/draft_versions/_form.html.erb

@@ -1,11 +1,18 @@
 <%= render "shared/globalize_locales", resource: @draft_version %>
 
-<%= translatable_form_for [:admin, @process, @draft_version], url: url do |f| %>
+<%= translatable_form_for [:admin, @process, @draft_version], url: url,
+  html: { data: { markdown_changes_message: I18n.t("admin.legislation.draft_versions.edit.markdown_changes_message") }} do |f| %>
 
   <%= render "shared/errors", resource: @draft_version %>
 
   <div class="row">
     <%= f.translatable_fields do |translations_form| %>
+      <div class="small-12 column">
+        <div class="callout warning" style="display: none;">
+          <%= t("admin.legislation.draft_versions.edit.warning") %>
+        </div>
+      </div>
+
       <div class="small-12 medium-9 column">
         <%= translations_form.text_field :title,
                                          placeholder: t("admin.legislation.draft_versions.form.title_placeholder") %>

app/views/admin/legislation/draft_versions/edit.html.erb

@@ -11,12 +11,6 @@
 
     <%= render "admin/legislation/processes/subnav", process: @process, active: "draft_versions" %>
 
-    <div class="small-12 column">
-      <div class="callout warning" data-markdown-changes-message="<%= I18n.t("admin.legislation.draft_versions.edit.markdown_changes_message") %>" style="display: none;">
-        <%= t("admin.legislation.draft_versions.edit.warning") %>
-      </div>
-    </div>
-
     <div class="small-12 column">
       <h3 class="inline-block"><%= @draft_version.title %></h3>
 

spec/system/admin/legislation/draft_versions_spec.rb

@@ -102,6 +102,8 @@ describe "Admin legislation draft versions" do
       visit path
       fill_in_markdown_editor "Text", with: "Version 1b"
 
+      expect(page).to have_content "You've edited the text"
+
       dismiss_confirm(prompt) do
         click_link "Proposals", match: :first
       end
@@ -141,7 +143,11 @@ describe "Admin legislation draft versions" do
       expect(page).to have_css("h2", text: "Proposals")
 
       go_back
+
       fill_in_markdown_editor "Text", with: "Version 1"
+
+      expect(page).not_to have_content "You've edited the text"
+
       click_link "Proposals", match: :first
 
       expect(page).to have_css("h2", text: "Proposals")