maint: update .gitignore. * .gitignore: ignore *~ .# and (from Zack Weinberg, autosave files) .*.sw[op] \#*#, closer to matching Autoconf. https://lists.gnu.org/archive/html/automake-patches/2021-12/msg00005.html https://lists.gnu.org/archive/html/automake-patches/2021-12/msg00010.html