r.kappa: fix omission typo (#433)

Co-authored-by: Markus Neteler <neteler@mundialis.de>

raster/r.kappa/calc_kappa.c

@@ -71,8 +71,8 @@ void calc_kappa(void)
 	else
 	    kpp[i] = (pii[i] - pi[i] * pj[i]) / (pi[i] - pi[i] * pj[i]);
 
-    /* print out the commission and ommission accuracy, and conditional kappa */
-    fprintf(fd, "\nCats\t%% Commission\t%% Ommission\tEstimated Kappa\n");
+    /* print out the comission and omission accuracy, and conditional kappa */
+    fprintf(fd, "\nCats\t%% Comission\t%% Omission\tEstimated Kappa\n");
     for (i = 0; i < ncat; i++)
 	if ((kpp[i] == -999) && (i != 0))
 	    fprintf(fd, "%ld\tNA\t\tNA\t\tNA\n", rlst[i]);

raster/r.kappa/r.kappa.html

@@ -10,7 +10,7 @@ respects the current geographic region and mask settings.
 two map layers and prepares the table from which the report
 is to be created.  <em>kappa</em> values for overall and
 each classes are computed along with their variances. Also
-percent of commission and ommission error, total correct
+percent of comission and omission error, total correct
 classified result by pixel counts, total area in pixel
 counts and percentage of overall correctly classified
 pixels are tabulated.