Modify the script that generates the CMake presets schema to extract the
list of available diagnostics from the `cmDiagnostics.h` header and
generate the relevant properties. This information is combined with a
partial set that remains in the YAML for those diagnostics whose
definitions differ from what is easily generated. While these special
cases will remain, the addition of new diagnostics should no longer
require manual updates to the YAML. (The presets version log will still
require manual updates.)