chore(pgsql): update comments of pg_hugepage.yml

Author: waitingsong

roles/pgsql/tasks/pg_hugepage.yml

@@ -5,7 +5,12 @@
 # support usage:
 #   - `pig install`
 #   - `bin/pgsql-add <pg_cls>`
+#   - `bin/pgsql-add <pg_cls> <ip>`
+#      service of nodes in ansible_play_hosts_all will be unavailable during the process, other nodes in the same pg_cls ignored
 #   - `pgsql.yml -l <pg_cls> -t pg_hugepage`
+#      entire service of this postgres cluster will be unavailable during the process
+#   - `pgsql.yml -l '<ip>,&<pg_cls>' -t pg_hugepage`
+#      service of nodes in ansible_play_hosts_all will be unavailable during the process, other nodes in the same pg_cls ignored
 #--------------------------------------------------------------#
 # calculation rules:
 #   1. `shared_memory_size_in_huge_pages` (from PG15+): if `node_hugepage_count` is -1 and huge_pages (from PG) != off