[processing] fix wrong parameter GRASS

Author: ghtmtt

python/plugins/processing/algs/grass7/description/r.thin.txt

@@ -2,5 +2,5 @@ r.thin
 Thins non-zero cells that denote linear features in a raster layer.
 Raster (r.*)
 QgsProcessingParameterRasterLayer|input|Input raster layer to thin|None|False
-QgsProcessingParameterNumber|maxit|Maximum number of iterations|QgsProcessingParameterNumber.Integer|200|True|1|None
+QgsProcessingParameterNumber|iterations|Maximum number of iterations|QgsProcessingParameterNumber.Integer|200|True|1|None
 QgsProcessingParameterRasterDestination|output|Thinned