[glib/wip/hadess/timer-docs] gtestutils: Mention the unit used for the test timer

[Bastien Nocera <hadess src gnome org>]

commit 0cc75eb72832ecf281c24f04570e20b382fcf844
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Dec 1 11:18:47 2021 +0100

    gtestutils: Mention the unit used for the test timer

 glib/gtestutils.c | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)
---
diff --git a/glib/gtestutils.c b/glib/gtestutils.c
index 578270394..45fc4a654 100644
--- a/glib/gtestutils.c
+++ b/glib/gtestutils.c
@@ -1900,9 +1900,10 @@ g_test_timer_start (void)
 /**
  * g_test_timer_elapsed:
  *
- * Get the time since the last start of the timer with g_test_timer_start().
+ * Get the number of seconds since the last start of the timer with
+ * g_test_timer_start().
  *
- * Returns: the time since the last start of the timer, as a double
+ * Returns: the time since the last start of the timer in seconds, as a double
  *
  * Since: 2.16
  */