remove notice to say format with spaces not tabs

both are valid now according to the ExtensionHarvester.cs file:

        private static bool IsFeatureFieldDeclaration(string line) {
            if (line.StartsWith("\t\t") ||
                line.StartsWith("\t    ") ||
                line.StartsWith("    ") ||
                line.StartsWith("    \t"))
                return true;

            return false;
        }