Run the `Utilities/Sphinx/update_versions.py` script to add initial markup to every top-level document and find module. Issue: #19715
Extend the change from commit 1d00ba9ccf (Find: find_package prefers variable CMAKE_FIND_USE_REGISTRY, 2018-11-13, v3.16.0-rc1~461^2~1) to cover the system package registry too. Fixes: #19890
1d00ba9ccf