manual typo fix (OSGeo#1268)

raster/r.clump/r.clump.html

@@ -31,7 +31,7 @@ <h2>DESCRIPTION</h2>
 cells is used to determine the similarity of two cells. This means that 
 input maps must be metric: the difference cell 1 - cell 2 must make 
 sense. Categorical maps, e.g. land cover, can not be used in this case. 
-Examples for valid inpat maps are satellite imagery, vegetation 
+Examples for valid input maps are satellite imagery, vegetation 
 indices, elevation, climatic parameters etc.
 
 <h2>NOTES</h2>