Add name_de to documentation

layers/poi/poi.yaml

@@ -7,7 +7,8 @@ layer:
   srs: +proj=merc +a=6378137 +b=6378137 +lat_ts=0.0 +lon_0=0.0 +x_0=0.0 +y_0=0.0 +k=1.0 +units=m +nadgrids=@null +wktext +no_defs +over
   fields:
     name: The OSM [`name`](http://wiki.openstreetmap.org/wiki/Key:name) value of the POI.
-    name_en: The english `name:en` value if available.
+    name_en: English name `name:en` if available, otherwise `name`.
+    name_de: German name `name:de` if available, otherwise `name` or `name:en`.
     class: |
         More general classes of POIs. If there is no more general `class` for the `subclass`
         this field will contain the same value as `subclass`.