r.out.png: lower-case keywords

	   note r.in.png in the manual


git-svn-id: https://svn.osgeo.org/grass/grass/trunk@51205 15284696-431f-4ddb-bdfa-cd5b030d7da7

raster/r.out.png/main.c

@@ -111,7 +111,7 @@ int main(int argc, char *argv[])
     module = G_define_module();
     G_add_keyword(_("raster"));
     G_add_keyword(_("export"));
-    G_add_keyword("PNG");
+    G_add_keyword("png");
     module->description =
 	_("Export a GRASS raster map as a non-georeferenced PNG image.");
 

raster/r.out.png/r.out.png.html

@@ -16,7 +16,8 @@ file will be called <tt>png_map.wld</tt>.
 <a href="r.out.gdal.html">r.out.gdal</a>,
 <a href="r.out.ppm.html">r.out.ppm</a>,
 <a href="r.out.tiff.html">r.out.tiff</a>,
-<a href="r.out.ascii.html">r.out.ascii</a>
+<a href="r.out.ascii.html">r.out.ascii</a>,
+<a href="r.in.png.html">r.in.png</a>
 </em>