util: move diff_parent from logcmdutil to diffutil This function will be used outside of the log command (in templatekw, used by hgweb, for which logcmdutil is not available). Let's move this function together with the rest of the diff-related utils instead.

logcmdutil: return structured diffstat data for json

cleanup: drop the `bytes` compatibility for attribute related function We can rely on the builtins directly now.

cleanup: turn `wrapfunction` deprecation warning into an error We could simply drop the check, but lets raise explicit error instead of suffering strange error in case of misuse.

cleanup: turn `wrappedfunction` deprecation warning into an error We could simply drop the check, but lets raise explicit error instead of suffering strange error in case of misuse.

cleanup: turn `pathsuboption` deprecation warning into an error We could simply drop the check, but lets raise explicit error instead of suffering strange error in case of misuse.

cleanup: drop deprecated config attribute on the revlog class This code was marked for deletion in the next cycle. We are now in the next cycle.

cleanup: drop `path.pushloc` deprecated since 6.5 This was scheduled for removal, let us remove it.

cleanup: drop `dirstate.is_changing_parent` deprecated since 6.5 This was scheduled for removal, let us remove it.

cleanup: remove some code scheduled to be removed after 5.9 looks like we missed this when cleaning up previous code.