Bug 1423716: stop adding the SEO root title to all document titles

We currently constuct the <title> of a document like this:

  <title> - <SEO root document title> | MDN

So for https://developer.mozilla.org/en-US/docs/Learn/CSS we have:

  Learn to style HTML using CSS - Learn web development | MDN

This patch shortens the title by removing the SEO root title, leaving:

  Learn to style HTML using CSS | MDN

kuma/wiki/jinja2/wiki/document.html

@@ -1,5 +1,5 @@
 {% extends "wiki/base.html" %}
-{% block title %}{{ page_title(document.title + seo_parent_title) }}{% endblock %}
+{% block title %}{{ page_title(document.title) }}{% endblock %}
 
 {% from "wiki/includes/document_macros.html" import build_document_crumbs, get_document_quick_links, document_watch, contributor_links with context %}
 {% from "wiki/includes/buttons.html" import get_document_buttons with context %}

kuma/wiki/views/document.py

@@ -111,29 +111,6 @@ def _make_doc_structure(document, level, expand, depth):
     return result
 
 
-def _get_seo_parent_title(document, slug_dict, document_locale):
-    """
-    Get parent-title information for SEO purposes.
-    """
-    seo_doc_slug = slug_dict['seo_root']
-    seo_root_doc = None
-
-    if seo_doc_slug:
-        # If the SEO root doc is the parent topic, save a query
-        if document.parent_topic_id and document.parent_topic.slug == seo_doc_slug:
-            seo_root_doc = document.parent_topic
-        else:
-            try:
-                seo_root_doc = Document.objects.only('title').get(locale=document_locale, slug=seo_doc_slug)
-            except Document.DoesNotExist:
-                pass
-
-    if seo_root_doc:
-        return u' - {}'.format(seo_root_doc.title)
-    else:
-        return ''
-
-
 def _filter_doc_html(request, doc, doc_html, rendering_params):
     """
     Apply needed filtering/annotating operations to a Document's HTML.
@@ -705,10 +682,6 @@ def document(request, document_slug, document_locale):
         # Get the SEO summary
         seo_summary = doc.get_summary_text()
 
-        # Get the additional title information, if necessary.
-        seo_parent_title = _get_seo_parent_title(
-            original_doc, slug_dict, document_locale)
-
         # Retrieve pre-parsed content hunks
         quick_links_html = doc.get_quick_links_html()
         body_html = doc.get_body_html()
@@ -752,7 +725,6 @@ def document(request, document_slug, document_locale):
             ),
             'render_raw_fallback': rendering_params['render_raw_fallback'],
             'seo_summary': seo_summary,
-            'seo_parent_title': seo_parent_title,
             'share_text': share_text,
             'search_url': get_search_url_from_referer(request) or '',
             'analytics_page_revision': doc.current_revision_id,