[gdal-dev] small typo in dox for gdal_sieve

[Vincent Schut]

Frank,

a small typo has slipped into the gdal_sieve.dox file:

-4:
     Four connectedness should be used when determining polygons. That 
is diagonal pixels are not considered directly connected. This is the 
default.

-4:
     Eight connectedness should be used when determining polygons. That 
is diagonal pixels are considered directly connected.

obviously should be:

-4:
     Four connectedness should be used when determining polygons. That 
is diagonal pixels are not considered directly connected. This is the 
default.

-8:
     Eight connectedness should be used when determining polygons. That 
is diagonal pixels are considered directly connected.

(change second -4 into -8)

Cheers,
Vincent.