Add the Web Browser Engineering book (#11567)

* Add the Web Browser Engineering book

* List in alphabetic order

books/free-programming-books-subjects.md

@@ -918,6 +918,7 @@ Kerridge (PDF) (email address *requested*, not required)
 * [The Catalog of Design Patterns](https://refactoring.guru/design-patterns/catalog)
 * [The Site Reliability Workbook](https://landing.google.com/sre/workbook/toc/) - Betsy Beyer, Niall Richard Murphy, David K. Rensin, Kent Kawahara, Stephen Thorne
 * [Web API Design](https://pages.apigee.com/rs/apigee/images/api-design-ebook-2012-03.pdf) - Brian Mulloy (PDF)
+* [Web Browser Engineering](https://browser.engineering/index.html) - Pavel Panchekha, Chris Harrelson
 * [Working with Web APIs](https://launchschool.com/books/working_with_apis) - Launch School
 * [Your API Is Bad](https://leanpub.com/yourapiisbad/read) - Paddy Foran