doc: Add documentation for ipv4.dhcp.routes config

Author: gwenya

doc/.wordlist.txt

@@ -65,6 +65,7 @@ Diátaxis
 Diffie
 Distrobuilder
 DNS
+dnsmasq
 DNSSEC
 DoS
 DRM

doc/reference/network_bridge.md

@@ -75,6 +75,7 @@ Key                                  | Type      | Condition             | Defau
 `ipv4.dhcp.expiry`                   | string    | IPv4 DHCP             | `1h`                      | When to expire DHCP leases
 `ipv4.dhcp.gateway`                  | string    | IPv4 DHCP             | IPv4 address              | Address of the gateway for the subnet
 `ipv4.dhcp.ranges`                   | string    | IPv4 DHCP             | all addresses             | Comma-separated list of IP ranges to use for DHCP (FIRST-LAST format)
+`ipv4.dhcp.routes`                   | string    | IPv4 DHCP             | -                         | Static routes to provide via DHCP option 121, as a comma-separated list of alternating subnets (CIDR) and gateway addresses (same syntax as dnsmasq)
 `ipv4.firewall`                      | bool      | IPv4 address          | `true`                    | Whether to generate filtering firewall rules for this network
 `ipv4.nat`                           | bool      | IPv4 address          | `false` (initial value on creation if `ipv4.address` is set to `auto`: `true`) | Whether to NAT
 `ipv4.nat.address`                   | string    | IPv4 address          | -                         | The source address used for outbound traffic from the bridge

doc/reference/network_ovn.md

@@ -52,6 +52,7 @@ Key                                  | Type      | Condition             | Defau
 `dns.zone.reverse.ipv6`              | string    | -                     | -                         | DNS zone name for IPv6 reverse DNS records
 `ipv4.address`                       | string    | standard mode         | - (initial value on creation: `auto`) | IPv4 address for the bridge (use `none` to turn off IPv4 or `auto` to generate a new random unused subnet) (CIDR)
 `ipv4.dhcp`                          | bool      | IPv4 address          | `true`                    | Whether to allocate addresses using DHCP
+`ipv4.dhcp.routes`                   | string    | IPv4 DHCP             | -                         | Static routes to provide via DHCP option 121, as a comma-separated list of alternating subnets (CIDR) and gateway addresses (same syntax as dnsmasq and OVN)
 `ipv4.l3only`                        | bool      | IPv4 address          | `false`                   | Whether to enable layer 3 only mode.
 `ipv4.nat`                           | bool      | IPv4 address          | `false` (initial value on creation if `ipv4.address` is set to `auto`: `true`) | Whether to NAT
 `ipv4.nat.address`                   | string    | IPv4 address          | -                         | The source address used for outbound traffic from the network (requires uplink `ovn.ingress_mode=routed`)