wiki pages: fix error when force renaming wiki page.

Bug: force renaming a wiki page fails. Fix: use the wiki page id instead
of the title in the update action.

app/views/wiki_pages/new.html.erb

@@ -9,7 +9,16 @@
     </div>
   <% end %>
 
-  <%= render "form" %>
+  <%= error_messages_for("wiki_page") %>
+
+  <%= simple_form_for(@wiki_page) do |f| %>
+    <%= f.input :title, error: false, input_html: { data: { autocomplete: "tag" } } %>
+    <%= f.input :other_names_string, as: :text, input_html: { size: "30x1" }, label: "Other names (#{link_to_wiki "help", "help:translated_tags"})".html_safe, hint: "Names used for this tag on other sites such as Pixiv. Separate with spaces." %>
+    <%= dtext_field "wiki_page", "body" %>
+    <%= f.submit "Submit" %>
+    <%= dtext_preview_button "wiki_page", "body" %>
+  <% end %>
+
   <%= wiki_page_alias_and_implication_list(@wiki_page)%>
   <%= wiki_page_post_previews(@wiki_page) %>
 <% end %>