Update comment regarding alumni team

Author: dtolnay

teams/alumni.toml

@@ -1,10 +1,12 @@
-# DEPRECATED: Do not add new members to this team, instead add to `people.alumni`
-# in the team's file or create a new `people.alumni` key and add the
-# person's name there instead.
 name = "alumni"
 
 [people]
 leads = []
+# Contributors whose former teams no longer correspond to any page on the
+# current website.
+#
+# When adding an alumnus to a team that still exists, please add to
+# `people.alumni` in that team's file, instead of here.
 members = [
     "alercah",
     "birkenfeld",
@@ -14,8 +16,7 @@ members = [
     "valgrimm",
     "whitequark",
 ]
-# Temporary key that includes all members listed as alumni in the individual
-# teams. This is needed while we migrate away from the alumni team.
+# Include all members listed as alumni in the individual teams.
 include-all-alumni = true
 
 [website]