docs: document new mesh.batman_adv.routing_algo settings for coexistence

docs/multidomain-site-example/domains/alpha_centauri.conf

@@ -41,6 +41,12 @@
     },
   },
 
+  mesh = {
+    batman_adv = {
+      routing_algo = 'BATMAN_IV',
+    },
+  },
+
   mesh_vpn = {
     fastd = {
       groups = {

docs/site-example/site.conf

@@ -74,6 +74,9 @@
 
   mesh = {
     vxlan = true,
+    batman_adv = {
+      routing_algo = 'BATMAN_IV',
+    },
   },
 
   -- The next node feature allows clients to always reach the node it is

docs/user/site.rst

@@ -238,8 +238,15 @@ mesh
     In addition, options specific to the batman-adv routing protocol can be set
     in the *batman_adv* section:
 
-    The optional value *routing_algo* allows to set up ``BATMAN_V`` based meshes. 
-    If unset, the routing algorithm will default to ``BATMAN_IV``.
+    The mandatory value *routing_algo* selects the batman-adv protocol variant.
+    The following values are supported:
+
+    - ``BATMAN_IV_LEGACY`` (*mesh-batman-adv-14*)
+    - ``BATMAN_IV`` (*mesh-batman-adv-15*)
+    - ``BATMAN_V`` (*mesh-batman-adv-15*)
+
+    When both *mesh-batman-adv-14* and *mesh-batman-adv-15* are included, this
+    setting specifies which one to use.
 
     The optional value *gw_sel_class* sets the gateway selection class, the
     default is ``20`` for B.A.T.M.A.N. IV and ``5000`` kbit/s for B.A.T.M.A.N. V.