feat: Allow passing in '-' when doing do-init.sh

This backwards compatibility feature doesn't cost anything, it shouldn't
have been removed in the first place. Not to mention, this specific
argument interface for initialization in general for command line tools

Author: hyperupcall

pkg/lib/commands/do-init.sh

@@ -22,6 +22,10 @@ echo_posix_shell_variables() {
 # - Sourcing bpm completion
 # - Sourcing 'include' function
 do-init() {
+	if [ "$1" == '-' ]; then
+		shift
+	fi
+
 	local shell="$1"
 
 	if [ -z "$shell" ]; then