typo 'douible' in gvpr man page

From man gvpr:

       X : douible
              the X coordinate of a node. (Assumes the node has a pos attribute.)

       Y : douible
              the Y coordinate of a node. (Assumes the node has a pos attribute.)

Note typo 'douible' instead of double.

Find a patch attached: 0001-Fix-typo-douible-in-gvpr.1.patch