Add pg_settings units display for "commit_delay" (ms).

Also remove unnecessary units designation in postgresql.conf.sample.

src/backend/utils/misc/guc.c

@@ -2033,7 +2033,8 @@ static struct config_int ConfigureNamesInt[] =
 		{"commit_delay", PGC_USERSET, WAL_SETTINGS,
 			gettext_noop("Sets the delay in microseconds between transaction commit and "
 						 "flushing WAL to disk."),
-			NULL
+			NULL,
+			GUC_UNIT_MS
 		},
 		&CommitDelay,
 		0, 0, 100000,

src/backend/utils/misc/postgresql.conf.sample

@@ -137,7 +137,7 @@
 
 # - Cost-Based Vacuum Delay -
 
-#vacuum_cost_delay = 0ms		# 0-100 milliseconds
+#vacuum_cost_delay = 0			# 0-100 milliseconds
 #vacuum_cost_page_hit = 1		# 0-10000 credits
 #vacuum_cost_page_miss = 10		# 0-10000 credits
 #vacuum_cost_page_dirty = 20		# 0-10000 credits