format: change to edt.: role

Definition list at https://www.loc.gov/marc/relators/relaterm.html

Author: davorpa

books/free-programming-books-langs.md

@@ -491,7 +491,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 
 * [A Complete Guide to Standard C++ Algorithms](https://github.com/HappyCerberus/book-cpp-algorithms) - Šimon Tóth (PDF, LaTeX) (:construction: *in process*)
 * [C++ Annotations](https://fbb-git.gitlab.io/cppannotations/) - Frank B. Brokken (HTML, PDF)
-* [C++ Core Guidelines](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md) - Editors: Bjarne Stroustrup, Herb Sutter
+* [C++ Core Guidelines](https://github.com/isocpp/CppCoreGuidelines/blob/master/CppCoreGuidelines.md) - `edt.:` Bjarne Stroustrup, Herb Sutter
 * [C++ GUI Programming With Qt 3](https://ptgmedia.pearsoncmg.com/images/0131240722/downloads/blanchette_book.pdf) - Jasmin Blanchette, Mark Summerfield (PDF)
 * [C++ Language](http://www.cplusplus.com/doc/tutorial/)
 * [C++ Notes for Professionals](https://goalkicker.com/CPlusPlusBook) - Compiled from StackOverflow Documentation (PDF)