WebGUI DHCP server page - lacks heading for static IP mapping section

[dhatz]

While looking at the webGUI - Services - DHCP Server page, I noticed that it might not be clear to a newcomer where one adds "static" IP mappings in pfsense's DHCP server.

A heading & short description should probably be added at the section the bottom of the DHCP server tab.

[jimp]

Good point.

https://github.com/bsdperimeter/pfsense/commit/f2ea45ef4717f489d40e93d392fa3355d22141a6
https://github.com/bsdperimeter/pfsense/commit/ee6bd11d4c2988a32050c19841bbcf080ed3e602