docs: fix broken SmartBear code review link

[nothing-991]

Fixes a broken reference link in development documentation by replacing
the dead SmartBear PDF with the current article URL.

[nothing-991]

Hi @ichard26 / maintainers
I fixed the broken link in docs/html/development/contributing.rst by replacing the outdated PDF URL with the current SmartBear page for peer code review best practices.
I also verified that all checks are now passing.
Please let me know if you’d like me to update any additional links in the development docs. Thanks!

[ichard26]

Thanks!

The publisher seems to have updated the best practices a bit comparing to the archived PDF on the Wayback Machine, but it still looks relevant.

[ichard26]

@nothing-991 If you'd like, you can try your hand at fixing all of the links in the development folder. They all seem not too bad to fix.

[nothing-991]

Hi @ichard26, thanks!
I checked the links in the development folder and so far the only broken one I found was the archived PDF link, which I’ve fixed in this PR.
The remaining links appear to be working for me, but I’m happy to re-check or fix any specific ones you had in mind.