Add GParted Live USB flash drive tip to help manual (#734376)

Add tip that the GParted Live image can be written to a USB flash
drive to be used in computers that can boot from USB.

Bug 734376 - Add GRUB 2 Restore Steps to GParted Manual

help/C/gparted.xml

@@ -2303,6 +2303,16 @@
         </listitem>
       </itemizedlist>
     </para>
+    <tip>
+      <para>
+      The GParted Live CD image can be written to a USB flash drive.
+      </para>
+      <para>
+      If your computer can boot from Universal Serial Bus (USB) then
+      you might prefer to boot and use
+      <application>&app;</application> from a USB flash drive.
+      </para>
+    </tip>
     <tip>
       <para>
       To avoid wasting a blank CD when burning a CD image file,