Fix broken links to appendix pages from pages in CPU section

[handledexception]

While reading through the published version of the book, I ran into a broken link from the CPU Registers page to the Appendix Numbers page. I've gone through and fixed this and all of the other broken Appendix links in the CPU section of the book.

Example: https://rylev.github.io/DMG-01/public/book/cpu/appendix/numbers.html