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-sr.md

@@ -0,0 +1,8 @@
+### Index
+
+* [C](#c)
+
+
+### C
+
+* [Beej-ov vodič za mrežno programiranje - Korištenje Internet soket-a](https://web.archive.org/web/20181008134854/http://users.teol.net:80/~mvlado/sockets/) - Brian "Beej Jorgensen" Hall, Maksimović Darko (HTML) *(:card_file_box: archived)*