Manual cleanup and pgindent of pgstat and bufmgr related code

This is in preparation for commiting a larger patch series in the area.

Discussion: https://postgr.es/m/CAAKRu_bHwGEbzNxxy+MQDkrsgog6aO6iUvajJ4d6PD98gFU7+w@mail.gmail.com

src/backend/utils/activity/pgstat.c

@@ -426,7 +426,7 @@ pgstat_discard_stats(void)
 		ereport(DEBUG2,
 				(errcode_for_file_access(),
 				 errmsg_internal("unlinked permanent statistics file \"%s\"",
-						PGSTAT_STAT_PERMANENT_FILENAME)));
+								 PGSTAT_STAT_PERMANENT_FILENAME)));
 	}
 
 	/*
@@ -986,6 +986,7 @@ pgstat_build_snapshot(void)
 
 		entry->data = MemoryContextAlloc(pgStatLocal.snapshot.context,
 										 kind_info->shared_size);
+
 		/*
 		 * Acquire the LWLock directly instead of using
 		 * pg_stat_lock_entry_shared() which requires a reference.

src/backend/utils/activity/pgstat_relation.c

@@ -783,6 +783,7 @@ pgstat_relation_flush_cb(PgStat_EntryRef *entry_ref, bool nowait)
 	if (lstats->t_counts.t_numscans)
 	{
 		TimestampTz t = GetCurrentTransactionStopTimestamp();
+
 		if (t > tabentry->lastscan)
 			tabentry->lastscan = t;
 	}

src/backend/utils/adt/pgstatfuncs.c

@@ -906,7 +906,7 @@ pg_stat_get_backend_client_addr(PG_FUNCTION_ARGS)
 	clean_ipv6_addr(beentry->st_clientaddr.addr.ss_family, remote_host);
 
 	PG_RETURN_DATUM(DirectFunctionCall1(inet_in,
-										 CStringGetDatum(remote_host)));
+										CStringGetDatum(remote_host)));
 }
 
 Datum