Update entries for Beej's Guides (#6781)

* Update file formats available for Beej's Guide to Network Programming (books-by-language section)

* Add Beej's Guide to Network Programming (books-by-subject section)

* Add Beej's Guide to Network Programming (books-dk section)

* Add Beej's Guide to Network Programming (books-hu section)

* Add Beej's Guide to Network Programming (books-ro section)

* Add Beej's Guide to Network Programming (books-sr section)

* lint fixup: correction for number of blank lines between section and following heading

* lint fixup: alphabetical ordering correction

* Code review feedback: add missing table-of-contents entries

* Code review feedback: add missing archived annotations

* Code review feedback: add README locale entry for 'sr'

* Fixup: add missing file format annotation

* Fixup: add missing author entry

* Code review feedback: update author name attribution

* Code review feedback: add translation credits

* Fixup: consistency: update a few more author name entries

* Code review feedback: remove 'translated by' prefix before translator name

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

* Nitpick: remove redundant 'www' subdomain prefix from destination URL

* Code review feedback: remove entry from existing location under 'C' language (guideline: one entry per book per human-language; 'Networking' is approved as the better location)

Co-authored-by: David Ordás <3125580+davorpa@users.noreply.github.com>

books/free-programming-books-dk.md

@@ -9,6 +9,7 @@
 
 ### C
 
+* [Beej's Guide til Netvarksprogrammierung](https://web.archive.org/web/20190701062226/http://artcreationforever.com/bgnet.html) - Brian "Beej Jorgensen" Hall, Art of Science (HTML) *(:card_file_box: archived)*
 * [Programmering i C](http://people.cs.aau.dk/~normark/c-prog-06/pdf/all.pdf) - Kurt Nørmark (PDF)