update teaching

_includes/nav_en.html

@@ -1,7 +1,7 @@
 <nav>
 <ul>
 <li><a href="/en/publications">Publications</a></li>
-<li>Teaching <a href="/enseignement/">🇫🇷</a> · <a href="/de">🇩🇪</a></li>
+<li><a href="/en/teaching">Teaching</a></li>
 <li><a href="/en/cv">CV</a></li>
 <li><a href="/numérique/">Numerics</a></li>
 <li><a href="https://git.oknaj.eu/gjankowiak/">Code</a></li>

_layouts/default.html

@@ -52,7 +52,11 @@
                 <section>
                 <p class="switcher">
                 {% if page.lang == 'en' %}
+                    {% if page.fr_url == '' %}
                         <a href="{{ page.url | remove_first: '/en' }}">🇫🇷</a>
+                    {% else %}
+                        <a href="{{ page.fr_url }}">🇫🇷</a>
+                    {% endif %}
 
                       <a href="/de">🇩🇪</a>
                     </p>

enseignement/index.markdown

@@ -3,7 +3,7 @@ layout: default
 subtitle: Enseignement
 math: false
 lang: fr
-en_url: /enseignement
+en_url: /en/teaching
 ---
 
 # Paris-Dauphine (MIDO)