doc: correct punctuation and improve typography in documentation

man: update and extend the various sd_bus_message_append_*() man pages Some calls changed their signature since the man pages were written. Also extend on a number of details.

man: revert dynamic paths for split-usr setups This did not really work out as we had hoped. Trying to do this upstream introduced several problems that probably makes it better suited as a downstream patch after all. At any rate, it is not releaseable in the current state, so we at least need to revert this before the release. * by adjusting the path to binaries, but not do the same thing to the search path we end up with inconsistent man-pages. Adjusting the search path too would be quite messy, and it is not at all obvious that this is worth the effort, but at any rate it would have to be done before we could ship this. * this means that distributed man-pages does not make sense as they depend on config options, and for better or worse we are still distributing man pages, so that is something that definitely needs sorting out before we could ship with this patch. * we have long held that split-usr is only minimally supported in order to boot, and something we hope will eventually go away. So before we start adding even more magic/effort in order to make this work nicely, we should probably question if it makes sense at all.

man: always build sd-bus man pages, even if kdbus is disabled After all, we now moved sd-bus out of the kdbus conditional, hence the man pages should be too.

man: generate configured paths in manpages In particular, use /lib/systemd instead of /usr/lib/systemd in distributions like Debian which still have not adopted a /usr merge setup. Use XML entities from man/custom-entities.ent to replace configured paths while doing XSLT processing of the original XML files. There was precedent of some files (such as systemd.generator.xml) which were already using this approach. This addresses most of the (manual) fixes from this patch: http://anonscm.debian.org/cgit/pkg-systemd/systemd.git/tree/debian/patches/Fix-paths-in-man-pages.patch?h=experimental-220 The idea of using generic XML entities was presented here: http://lists.freedesktop.org/archives/systemd-devel/2015-May/032240.html This patch solves almost all the issues, with the exception of: - Path to /bin/mount and /bin/umount. - Generic statements about preference of /lib over /etc. These will be handled separately by follow up patches. Tested: - With default configure settings, ran "make install" to two separate directories and compared the output to confirm they matched exactly. - Used a set of configure flags including $CONFFLAGS from Debian: http://anonscm.debian.org/cgit/pkg-systemd/systemd.git/tree/debian/rules Installed the tree and confirmed the paths use /lib/systemd instead of /usr/lib/systemd and that no other unexpected differences exist. - Confirmed that `make distcheck` still passes.

treewide: Correct typos and spell plural of bus consistent

man: fix a bunch of links All hail linkchecker!

man: boilerplate unification

man: add emacs header to get correct indention in nxml-mode for the manpage XML files that use 2ch indenting In the long run we really should figure out if we want to stick with 8ch or 2ch indenting, and not continue with half-and-half. For now, just make emacs aware of the files that use 2ch indenting.

man: add a mapping for external manpages It is annoying when we have dead links on fd.o. Add project='man-pages|die-net|archlinux' to <citerefentry>-ies. In generated html, add external links to http://man7.org/linux/man-pages/man, http://linux.die.net/man/, https://www.archlinux.org/. By default, pages in sections 2 and 4 go to man7, since Michael Kerrisk is the autorative source on kernel related stuff. The rest of links goes to linux.die.net, because they have the manpages. Except for the pacman stuff, since it seems to be only available from archlinux.org. Poor gummiboot gets no link, because gummitboot(8) ain't to be found on the net. According to common wisdom, that would mean that it does not exist. But I have seen Kay using it, so I know it does, and deserves to be found. Can somebody be nice and put it up somewhere?

doc: comma placement corrections and word order Set commas where there should be some. Some improvements to word order.

man: describe functions for appending to messages