[gtk+] SidebarRow: Add Unmount tooltip to eject_button

[Daniel Boles <dboles src gnome org>]

commit da76699757cdbda128cb2929a9100aec6d577a55
Author: Daniel Boles <dboles src gnome org>
Date:   Sat Aug 19 17:27:20 2017 +0100

    SidebarRow: Add Unmount tooltip to eject_button
    
    It was reported that the lack of a tooltip made its purpose unclear.
    This can be solved by just copying PlacesViewRow’s eject_button tooltip.
    
    https://bugzilla.gnome.org/show_bug.cgi?id=766909

 gtk/ui/gtksidebarrow.ui |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)
---
diff --git a/gtk/ui/gtksidebarrow.ui b/gtk/ui/gtksidebarrow.ui
index 8cb6380..9b590e2 100644
--- a/gtk/ui/gtksidebarrow.ui
+++ b/gtk/ui/gtksidebarrow.ui
@@ -37,6 +37,7 @@
                 <property name="valign">center</property>
                 <property name="margin-start">4px</property>
                 <property name="icon-name">media-eject-symbolic</property>
+                <property name="tooltip-text" translatable="yes">Unmount</property>
                 <style>
                   <class name="sidebar-button"/>
                 </style>