Update devel/kdevelop and attendant ports to latest upstream 5.4.1

Release announcement:
https://www.kdevelop.org/news/kdevelop-541-released

Various small bugfixes over 5.4.0, which was announced at
https://www.kdevelop.org/news/kdevelop-540-released

and *that* introduced Meson build support, Scratchpads, and clang-tidy.

The port chases upstream, with one exception: the QDebug categories
are specifically dropped back to "old" style, so they live in
${LOCALBASE}/etc/xdg with the rest, instead of the new-fangled
and we-need-to-think-about-this ${LOCALBASE}/share/qdebug-categories5/