wg-quick now supports specifying DNS searches as part of
DNS= setting.

See-also: https://lists.zx2c4.com/pipermail/wireguard/2020-May/005415.html
See-also: https://git.zx2c4.com/wireguard-tools/commit/?id=7f236c79570642d466c5acab890b26c3a07f4f7a