doc/userguide: add reload-tenant(s) doc

doc/userguide/configuration/multi-tenant.rst

@@ -218,6 +218,29 @@ Tenants can be mapped to vlan ids.
 The registration of tenant and tenant handlers can be done on a
 running engine.
 
+Reloads
+~~~~~~~
+
+Reloading all tenants:
+
+``reload-tenants``
+
+::
+
+  reload-tenants
+
+Reloading a single tenant:
+
+``reload-tenant <tenant id> [yaml path]``
+
+::
+
+  reload-tenant 1 tenant-1.yaml
+  reload-tenant 5
+
+The ``[yaml path]`` is optional. If it isn't provided, the original path of
+the tenant will be used during the reload.
+
 Eve JSON output
 ---------------
 

doc/userguide/partials/commands-sc.rst

@@ -88,6 +88,10 @@
    specified. If it is omitted, the original yaml that was used to load
    / last reload the tenant is used.
 
+.. describe:: reload-tenants
+
+   Reload all registered tenants by reloading their yaml.
+
 .. describe:: unregister-tenant <id>
 
    Unregister tenant with a particular ID.