Adding Pascal language references to books (#6971)

* Adding Pascal

Adding Pascal references

* Formatting and minor changes

Adding PDF/HTML tags and re-arranging into alphabetical order

* Fix alphabetical ordering

* Change author name

Co-authored-by: Eric Hellman <eric@hellman.net>

* More description for Turbo Pascal

Co-authored-by: Eric Hellman <eric@hellman.net>

* Adding author

Co-authored-by: Eric Hellman <eric@hellman.net>

* Add origin info

Co-authored-by: Eric Hellman <eric@hellman.net>

Co-authored-by: Eric Hellman <eric@hellman.net>

books/free-programming-books-langs.md

@@ -150,6 +150,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [OpenMP](#openmp)
 * [OpenResty](#openresty)
 * [OpenSCAD](#openscad)
+* [Pascal](#pascal)
 * [Perl](#perl)
 * [PHP](#php)
   * [CakePHP](#cakephp)
@@ -1653,6 +1654,19 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [TrueOS® Users Handbook](https://www.trueos.org/handbook/trueos.html)
 
 
+### Pascal
+
+* [Free Pascal Reference guide](https://www.freepascal.org/docs-html/ref/ref.html)
+* [Modern Object Pascal Introduction for Programmers](https://castle-engine.io/modern_pascal_introduction.html) (HTML)
+* [Pascal Language Reference](https://docs.oracle.com/cd/E19957-01/802-5762/802-5762.pdf) (PDF)
+* [Pascal Programming Reference Manual](https://public.support.unisys.com/aseries/docs/clearpath-mcp-17.0/pdf/86000080-103.pdf) - Unisys (PDF)
+* [Pascal Quick Reference](https://ksvi.mff.cuni.cz/~dingle/2017/pascal_reference.html)
+* [Turbo Pascal Reference Guide (1989)](http://bitsavers.org/pdf/borland/turbo_pascal/Turbo_Pascal_Version_5.0_Reference_Guide_1989.pdf) - Borland International (PDF)
+* [Vector Pascal, an Array Language](http://www.dcs.gla.ac.uk/~wpc/reports/compilers/compilerindex/vp-ver2.html) - Paul Cockshott, Greg Michaelson
+* [Vector Pascal Reference Manual](https://www.researchgate.net/publication/220177664_Vector_Pascal_reference_manual) (PDF)
+* [VSI Pascal for OpenVMS Reference Manual](https://vmssoftware.com/docs/VSI_PASCAL_REF.pdf) - VMS Software (PDF)
+
+
 ### Perl
 
 * [Beginning Perl](https://www.perl.org/books/beginning-perl/)