Update VLAN documentation

docs/models/ipam/vlan.md

@@ -1,6 +1,6 @@
 # VLANs
 
-A VLAN represents an isolated layer two domain, identified by a name and a numeric ID (1-4094) as defined in [IEEE 802.1Q](https://en.wikipedia.org/wiki/IEEE_802.1Q). Each VLAN may be assigned to a site, tenant, and/or VLAN group.
+A VLAN represents an isolated layer two domain, identified by a name and a numeric ID (1-4094) as defined in [IEEE 802.1Q](https://en.wikipedia.org/wiki/IEEE_802.1Q). VLANs are arranged into VLAN groups to define scope and to enforce uniqueness.
 
 Each VLAN must be assigned one of the following operational statuses:
 

docs/models/ipam/vlangroup.md

@@ -1,5 +1,5 @@
 # VLAN Groups
 
-VLAN groups can be used to organize VLANs within NetBox. Each group may optionally be assigned to a specific site, but a group cannot belong to multiple sites.
+VLAN groups can be used to organize VLANs within NetBox. Each VLAN group can be scoped to a particular region, site group, site, location, rack, cluster group, or cluster. Member VLANs will be available for assignment to devices and/or virtual machines within the specified scope.
 
 Groups can also be used to enforce uniqueness: Each VLAN within a group must have a unique ID and name. VLANs which are not assigned to a group may have overlapping names and IDs (including VLANs which belong to a common site). For example, you can create two VLANs with ID 123, but they cannot both be assigned to the same group.