[processing] fix GRASS 64 r.watershed

Author: Giovanni Manghi

python/plugins/processing/algs/grass/description/r.watershed.txt

@@ -8,12 +8,17 @@ ParameterRaster|disturbed.land|Percent of disturbed land, for USLE|True
 ParameterRaster|blocking|Terrain blocking overland surface flow, for USLE|True
 ParameterNumber|threshold|Minimum size of exterior watershed basin|None|None|0
 ParameterNumber|max.slope.length|Maximum length of surface flow, for USLE|None|None|0
+ParameterNumber|convergence|Convergence factor for MFD (1-10)|1|10|5
+ParameterNumber|memory|Maximum memory to be used with -m flag (in MB)|1|None|300
+ParameterBoolean|-f|SFD (D8) flow (default is MFD)|False
 ParameterBoolean|-4|Allow only horizontal and vertical flow of water|True
+ParameterBoolean|-m|Enable disk swap memory option (-m): Operation is slow|False
+ParameterBoolean|-a|Use positive flow accumulation even for likely underestimates|False
 OutputRaster|accumulation|Number of cells that drain through each cell
 OutputRaster|drainage|Drainage direction
 OutputRaster|basin|Unique label for each watershed basin
 OutputRaster|stream|Stream segments
 OutputRaster|half.basin|Half-basins output layer
 OutputRaster|visual|Visual display output layer
 OutputRaster|length.slope|Slope length and steepness (LS) factor for USLE
-OutputRaster|slope.steepness|Slope steepness (S) factor for USLE
+OutputRaster|slope.steepness|Slope steepness (S) factor for USLE