[gtksourceview] Rephrase docs added in last commit

[Paolo Borelli <pborelli src gnome org>]

commit 60b020df235451573a57e068703c4d61f0dff986
Author: Paolo Borelli <pborelli gnome org>
Date:   Sat Aug 15 12:45:02 2015 +0200

    Rephrase docs added in last commit

 gtksourceview/gtksourcecompletionproposal.c |    5 +++--
 gtksourceview/gtksourcecompletionprovider.c |    5 +++--
 2 files changed, 6 insertions(+), 4 deletions(-)
---
diff --git a/gtksourceview/gtksourcecompletionproposal.c b/gtksourceview/gtksourcecompletionproposal.c
index 2aeecb2..cb09ef8 100644
--- a/gtksourceview/gtksourcecompletionproposal.c
+++ b/gtksourceview/gtksourcecompletionproposal.c
@@ -35,8 +35,9 @@
  * the corresponding get function. Only one of those get functions
  * should return a value different from %NULL.
  * The icon may be specified as a #GdkPixbuf, as an icon name or as a #GIcon by
- * implementing the corresponding get function. Only one of those get functions
- * should return a value different from %NULL.
+ * implementing the corresponding get function. At most one of those get functions
+ * should return a value different from %NULL, if they all return %NULL no icon
+ * will be used.
  */
 
 #include "gtksourcecompletionproposal.h"
diff --git a/gtksourceview/gtksourcecompletionprovider.c b/gtksourceview/gtksourcecompletionprovider.c
index 248599d..1d465f1 100644
--- a/gtksourceview/gtksourcecompletionprovider.c
+++ b/gtksourceview/gtksourcecompletionprovider.c
@@ -31,8 +31,9 @@
  * The provider may be displayed in the completion window as a header row, showing
  * its name and optionally an icon.
  * The icon may be specified as a #GdkPixbuf, as an icon name or as a #GIcon by
- * implementing the corresponding get function. Only one of those get functions
- * should return a value different from %NULL.
+ * implementing the corresponding get function. At most one of those get functions
+ * should return a value different from %NULL, if they all return %NULL no icon
+ * will be used.
  */
 
 #include "gtksourcecompletionprovider.h"