This changes the procedure in UPDATING to use etcupdate over megemaster.
This follows the recommendations in the handbook commited from D27848.
UPDATING: Change update procedure to use etcupdate(8) over mergemaster(8) This commit aligns the steps in UPDATING with the steps from the handbook which already prefers etcupdate(8). While here also remove a dubious comment. PR: 252417 Reviewed by: 0mp, ceri, imp Approved by: philip (mentor) Differential Revision: https://reviews.freebsd.org/D28062 `