Log message:
*: latest py-sphinx only support Python 3.9+

Log message:
Mass-change BUILD_DEPENDS to TOOL_DEPENDS outside mk/.

Almost all uses, if not all of them, are wrong, according to the
semantics of BUILD_DEPENDS (packages built for target available for
use _by_ tools at build-time) and TOOL_DEPEPNDS (packages built for
host available for use _as_ tools at build-time).

No change to BUILD_DEPENDS as used correctly inside buildlink3.

As proposed on tech-pkg:
https://mail-index.netbsd.org/tech-pkg/2023/06/03/msg027632.html

Log message:
devel/py-dictdiffer: import py-dictdiffer-0.9.0

Dictdiffer is a helper module that helps you to diff and patch
dictionaries.