[gtk+] Settings: Mention Shift+primary click on Range too

[Daniel Boles <dboles src gnome org>]

commit 9c3479b605c55abc2cf8d57bb88e75b6034a99ca
Author: Daniel Boles <dboles src gmail com>
Date:   Wed Oct 11 22:35:31 2017 +0100

    Settings: Mention Shift+primary click on Range too
    
    This already existed, and since this doc blurb is already inflating
    dramatically, what’s another half a line?

 gtk/gtksettings.c |    3 ++-
 1 files changed, 2 insertions(+), 1 deletions(-)
---
diff --git a/gtk/gtksettings.c b/gtk/gtksettings.c
index 0753fee..a7b0c79 100644
--- a/gtk/gtksettings.c
+++ b/gtk/gtksettings.c
@@ -786,7 +786,8 @@ gtk_settings_class_init (GtkSettingsClass *class)
    * slider/value to move by the range’s page-size towards the point clicked.
    *
    * Whichever action you choose for the primary button, the other action will
-   * be available by clicking the middle mouse button (since GTK+ 3.22.25).
+   * be available by holding Shift and primary-clicking, or (since GTK+ 3.22.25)
+   * clicking the middle mouse button.
    *
    * Since: 3.6
    */