Add Pascal Programming by Wikibooks (EbookFoundation#7230)

Author: Double-A-92

Diff for: books/free-programming-books-langs.md

@@ -1643,6 +1643,7 @@ That section got so big, we decided to split it into its own file, the [BY SUBJE
 * [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](https://en.wikibooks.org/wiki/Pascal_Programming) - Wikibooks
 * [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)