[gnome-disk-utility] unlock dialog: Add tooltip for keyfile chooser button

[Kai Lüke <kailueke src gnome org>]

commit 9c400b15240d1fae922f28fa7b921fcb298206b4
Author: segfault <segfault riseup net>
Date:   Tue Nov 6 14:45:22 2018 +0100

    unlock dialog: Add tooltip for keyfile chooser button

 src/disks/ui/unlock-device-dialog.ui | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/src/disks/ui/unlock-device-dialog.ui b/src/disks/ui/unlock-device-dialog.ui
index 288086fc..810b3154 100644
--- a/src/disks/ui/unlock-device-dialog.ui
+++ b/src/disks/ui/unlock-device-dialog.ui
@@ -217,6 +217,7 @@
               <object class="GtkFileChooserButton" id="unlock-device-tcrypt-keyfile-chooser-button">
                 <property name="title" translatable="yes">Select a Keyfile</property>
                 <property name="visible">False</property>
+                <property name="tooltip_markup" translatable="yes">Select a keyfile to unlock this 
volume</property>
                 <property name="no_show_all">True</property>
                 <property name="can_focus">True</property>
               </object>