Plural State of logged message on injected files.

[johnkariuki]

Currently, the logged message on the number of injected files is statically set to plural state.

It would make sense to have the message reflect the correct plural state of the filesCount variable.

   if (filesCount) {
      var pluralState = filesCount > 1 ? 's' : '';
      log(cyan(filesCount) + ' file' + pluralState + ' into ' + magenta(target.relative) + '.');
    } else {
      log('Nothing to inject into ' + magenta(target.relative) + '.');
    }

This would look something like this.

[joakimbeng]

Closed by #193