Added XML documentation + link to source for luma function
Added XML documentation + link to source for luma function

rytmis/dotless,rytmis/dotless,r2i-sitecore/dotless,r2i-sitecore/dotless,r2i-sitecore/dotless,modulexcite/dotless,r2i-sitecore/dotless,r2i-sitecore/dotless,modulexcite/dotless,modulexcite/dotless,r2i-sitecore/dotless,dotless/dotless,modulexcite/dotless,r2i-sitecore/dotless,modulexcite/dotless,rytmis/dotless,rytmis/dotless,dotless/dotless,rytmis/dotless,modulexcite/dotless,rytmis/dotless,rytmis/dotless,modulexcite/dotless