Eli Schwartz authored May 03, 2018 and Allan McRae committed May 14, 2018

Since we no longer use vim-specific modelines, use the .asciidoc file
extension which is, well, reserved for asciidoc formatted files. This
should presumably work everywhere without needing editor-specific
workarounds and configuration.

Also add a shebang to makepkg.conf to indicate it contains bash content.

Signed-off-by: Eli Schwartz <eschwartz@archlinux.org>
Signed-off-by: Allan McRae <allan@archlinux.org>