[discretizers] re-add and deprecate neighbours

src/pymor/discretizers/builtin/grids/interfaces.py

@@ -10,6 +10,7 @@
 from pymor.core.logger import getLogger
 from pymor.discretizers.builtin.inverse import inv_transposed_two_by_two
 from pymor.discretizers.builtin.relations import inverse_relation
+from pymor.tools.deprecated import Deprecated
 
 
 class ReferenceElement(CacheableObject):
@@ -240,6 +241,10 @@ def _superentities_with_indices(self, codim, superentity_codim):
         SE = self.subentities(superentity_codim, codim)
         return inverse_relation(SE, size_rhs=self.size(codim), with_indices=True)
 
+    @Deprecated('neighbors')
+    def neighbours(self, *args, **kwargs):
+        self.neighbors(*args, **kwargs)
+
     def neighbors(self, codim, neighbor_codim, intersection_codim=None):
         """Maps entity index and local neighbor index to global neighbor index.