tr2: clarify TRACE2_PROCESS_INFO_EXIT comment under Linux

Rewrite a comment added in 2f732bf15e (tr2: log parent process name,
2021-07-21) to describe what we might do under
TRACE2_PROCESS_INFO_EXIT in the future, instead of vaguely referring
to "something extra".

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Acked-by: Taylor Blau <me@ttaylorr.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

compat/linux/procinfo.c

@@ -32,8 +32,12 @@ void trace2_collect_process_info(enum trace2_process_info_reason reason)
 	if (!trace2_is_enabled())
 		return;
 
-	/* someday we may want to write something extra here, but not today */
 	if (reason == TRACE2_PROCESS_INFO_EXIT)
+		/*
+		 * The Windows version of this calls its
+		 * get_peak_memory_info() here. We may want to insert
+		 * similar process-end statistics here in the future.
+		 */
 		return;
 
 	if (reason == TRACE2_PROCESS_INFO_STARTUP) {