skip external links in nav in sitemap (#1748)

Fixes #1742.

docs/about/release-notes.md

@@ -59,6 +59,7 @@ your global navigation uses more than one level, things will likely be broken.
 * Bugfix: Account for encoded URLs (#1670).
 * Bugfix: Ensure theme files do not override `docs_dir` files (#1671).
 * Bugfix: Do not normalize URL fragments (#1655).
+* Bugfix: Skip external URLs in sitemap.xml (#1742).
 * Add canonical tag to `readthedocs` theme (#1669).
 
 ## Version 1.0.4 (2018-09-07)

mkdocs/templates/sitemap.xml

@@ -4,11 +4,13 @@
             {{ nav_item(child) }}
         {%- endfor -%}
     {%- else %}
+	{%- if not item.is_link -%}
     <url>
      <loc>{% if item.canonical_url %}{{ item.canonical_url }}{% else %}{{ item.abs_url }}{% endif %}</loc>
      {% if item.update_date %}<lastmod>{{item.update_date}}</lastmod>{% endif %}
      <changefreq>daily</changefreq>
     </url>
+        {%- endif -%}
     {%- endif -%}
 {%- endmacro -%}