help: Use consistent capitalization for "NickServ"

All but one mention use "NickServ" over "Nickserv".

!181
4 jobs for !181 with scootergrisen-master-patch-37690 in 8 minutes and 11 seconds (queued for 5 seconds)
latest detached
Status Name Job ID Coverage
  Pre Review
passed check_commit_log #1387157

00:00:24

passed check-merge-request #1387158

00:00:26

 
  Review
passed eslint #1387159

00:00:33

 
  Build
passed flatpak #1387160
flatpak

00:07:11