Fix breadcrumb links.

See https://github.com/readthedocs/sphinx_rtd_theme/pull/1010

docs/source/_templates/breadcrumbs.html

@@ -15,21 +15,21 @@
         <!-- User defined GitHub URL -->
         <a href="{{ meta['github_url'] }}" class="fa fa-github"> {{ _('Edit on GitHub') }}</a>
       {% else %}
-        <a href="https://{{ github_host|default("github.com") }}/{{ github_user }}/{{ github_repo }}/{{ theme_vcs_pageview_mode|default("blob") }}/{{ github_version }}{{ conf_py_path }}{{ pagename }}{{ suffix }}" class="fa fa-github"> {{ _('Edit on GitHub') }}</a>
+        <a href="https://{{ github_host|default("github.com") }}/{{ github_user }}/{{ github_repo }}/{{ theme_vcs_pageview_mode or "blob" }}/{{ github_version }}{{ conf_py_path }}{{ pagename }}{{ suffix }}" class="fa fa-github"> {{ _('Edit on GitHub') }}</a>
       {% endif %}
       {% elif display_bitbucket %}
       {% if check_meta and 'bitbucket_url' in meta %}
         <!-- User defined Bitbucket URL -->
         <a href="{{ meta['bitbucket_url'] }}" class="fa fa-bitbucket"> {{ _('Edit on Bitbucket') }}</a>
       {% else %}
-        <a href="https://bitbucket.org/{{ bitbucket_user }}/{{ bitbucket_repo }}/src/{{ bitbucket_version}}{{ conf_py_path }}{{ pagename }}{{ suffix }}?mode={{ theme_vcs_pageview_mode|default("view") }}" class="fa fa-bitbucket"> {{ _('Edit on Bitbucket') }}</a>
+        <a href="https://bitbucket.org/{{ bitbucket_user }}/{{ bitbucket_repo }}/src/{{ bitbucket_version}}{{ conf_py_path }}{{ pagename }}{{ suffix }}?mode={{ theme_vcs_pageview_mode or "view" }}" class="fa fa-bitbucket"> {{ _('Edit on Bitbucket') }}</a>
       {% endif %}
       {% elif display_gitlab %}
       {% if check_meta and 'gitlab_url' in meta %}
         <!-- User defined GitLab URL -->
         <a href="{{ meta['gitlab_url'] }}" class="fa fa-gitlab"> {{ _('Edit on GitLab') }}</a>
       {% else %}
-        <a href="https://{{ gitlab_host|default("gitlab.com") }}/{{ gitlab_user }}/{{ gitlab_repo }}/{{ theme_vcs_pageview_mode|default("blob") }}/{{ gitlab_version }}{{ conf_py_path }}{{ pagename }}{{ suffix }}" class="fa fa-gitlab"> {{ _('Edit on GitLab') }}</a>
+        <a href="https://{{ gitlab_host|default("gitlab.com") }}/{{ gitlab_user }}/{{ gitlab_repo }}/{{ theme_vcs_pageview_mode or "blob" }}/{{ gitlab_version }}{{ conf_py_path }}{{ pagename }}{{ suffix }}" class="fa fa-gitlab"> {{ _('Edit on GitLab') }}</a>
       {% endif %}
       {% elif show_source and source_url_prefix %}
       <a href="{{ source_url_prefix }}{{ pagename }}{{ suffix }}">{{ _('View page source') }}</a>