Fix typo in ALTER SYSTEM output.

The header comment written into postgresql.auto.conf by ALTER SYSTEM
should match what initdb put there originally.

Feike Steenbergen

Discussion: https://postgr.es/m/CAK_s-G0KcKdO=0hqZkwb3s+tqZuuHwWqmF5BDsmoO9FtX75r0g@mail.gmail.com

src/backend/utils/misc/guc.c

@@ -6944,7 +6944,7 @@ write_auto_conf_file(int fd, const char *filename, ConfigVariable *head)
 
 	/* Emit file header containing warning comment */
 	appendStringInfoString(&buf, "# Do not edit this file manually!\n");
-	appendStringInfoString(&buf, "# It will be overwritten by ALTER SYSTEM command.\n");
+	appendStringInfoString(&buf, "# It will be overwritten by the ALTER SYSTEM command.\n");
 
 	errno = 0;
 	if (write(fd, buf.data, buf.len) != buf.len)