[gparted] Add note to README about needing gvfs to launch yelp

[Curtis Gedak <gedakc src gnome org>]

commit 7d3a504b6e1b446f8936919aead1f412f290e3d0
Author: Mike Fleetwood <mike fleetwood googlemail com>
Date:   Sat Jul 24 16:18:03 2021 +0100

    Add note to README about needing gvfs to launch yelp

 README | 1 +
 1 file changed, 1 insertion(+)
---
diff --git a/README b/README
index 13de9287..e837cf37 100644
--- a/README
+++ b/README
@@ -339,6 +339,7 @@ system.  These commands include:
                      available when gparted source is configured
    udevadm         - used in dmraid to query udev name
    yelp            - used to display help manual
+                     (requires gvfs to be able to launch yelp)
    xhost           - used to grant root access to the X11 server, only
                      when configured to do so