Make ctags.kak compatible with original awk

Positional arguments in awk’s printf is a feature that is only available
in the GNU implementation of awk (gawk). So the ctags auto-completion feature
was broken in Kakoune if the installed version of awk was nawk or mawk.
This simple change makes it retro-compatible with those versions.

See https://www.gnu.org/software/gawk/manual/html_node/Printf-Ordering.html

rc/tools/ctags.kak

@@ -72,7 +72,7 @@ define-command ctags-complete -docstring "Complete the current selection" %{
                 eval "set -- $kak_quoted_opt_ctagsfiles"
                 for ctagsfile in "$@"; do
                     ${kak_opt_readtagscmd} -p -t "$ctagsfile" ${kak_selection}
-                done | awk '{ uniq[$1]++ } END { for (elem in uniq) printf " %1$s||%1$s", elem }'
+                done | awk '{ uniq[$1]++ } END { for (elem in uniq) printf " %s||%s", elem, elem }'
             )
             printf %s\\n "evaluate-commands -client ${kak_client} set-option buffer=${kak_bufname} ctags_completions ${header}${compl}" | \
                 kak -p ${kak_session}