CLI: Fixes source-map-url description. (less#2264)

lib/less-node/lessc-helper.js

@@ -43,7 +43,7 @@ var lessc_helper = {
  console.log(" --source-map-basepath=X Sets sourcemap base path, defaults to current working directory.");
  console.log(" --source-map-less-inline puts the less files into the map instead of referencing them");
  console.log(" --source-map-map-inline puts the map (and any less files) into the output css file");
- console.log(" --source-map-url=URL the complete url and filename put in the less file");
+ console.log(" --source-map-url=URL the complete custom URL to map file for sourceMappingURL comment");
  console.log(" -rp, --rootpath=URL Set rootpath for url rewriting in relative imports and urls.");
  console.log(" Works with or without the relative-urls option.");
  console.log(" -ru, --relative-urls re-write relative urls to the base less file.");