homogenize keywords

git-svn-id: https://svn.osgeo.org/grass/grass/trunk@52836 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.to.rast3/main.c

@@ -195,7 +195,7 @@ int main(int argc, char *argv[])
 
     module = G_define_module();
     G_add_keyword(_("raster"));
-    G_add_keyword(_("volume"));
+    G_add_keyword(_("voxel"));
     G_add_keyword(_("conversion"));
     module->description =
         _("Converts 2D raster map slices to one 3D raster volume map.");

vector/v.to.rast3/main.c

@@ -46,7 +46,7 @@ int main(int argc, char *argv[])
 
     module = G_define_module();
     G_add_keyword(_("vector"));
-    G_add_keyword(_("volume"));
+    G_add_keyword(_("voxel"));
     G_add_keyword(_("conversion"));
     module->description = _("Converts a vector map "
 			    "(only points) into a 3D raster map.");

vector/v.vol.rst/main.c

@@ -238,6 +238,7 @@ int main(int argc, char *argv[])
 
     module = G_define_module();
     G_add_keyword(_("vector"));
+    G_add_keyword(_("voxel"));
     G_add_keyword(_("surface"));
     G_add_keyword(_("interpolation"));
     G_add_keyword(_("RST"));