[glib] gstrfuncs: Document the behaviour of g_strjoinv()

[Bastien Nocera <hadess src gnome org>]

commit 283c565af6a8a68015a078776c10f7103ba2c485
Author: Bastien Nocera <hadess hadess net>
Date:   Wed Mar 23 18:23:05 2016 +0100

    gstrfuncs: Document the behaviour of g_strjoinv()
    
    The behaviour of g_strjoinv() isn't explicitely explained when the array
    contains less than 2 items. This removes the guesswork.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=764092

 glib/gstrfuncs.c |    4 ++++
 1 files changed, 4 insertions(+), 0 deletions(-)
---
diff --git a/glib/gstrfuncs.c b/glib/gstrfuncs.c
index 975be0b..35491bb 100644
--- a/glib/gstrfuncs.c
+++ b/glib/gstrfuncs.c
@@ -2539,6 +2539,10 @@ g_strdupv (gchar **str_array)
  * optional @separator inserted between each of them. The returned string
  * should be freed with g_free().
  *
+ * If @str_array has no items, the return value will be an
+ * empty string. If @str_array contains a single item, @separator will not
+ * appear in the resulting string.
+ *
  * Returns: a newly-allocated string containing all of the strings joined
  *     together, with @separator between them
  */