Don't wrap $? in quotes

src/bin/dotify

@@ -108,4 +108,4 @@ case "$command" in
     ;;
 esac
 
-exit "$?"
+exit $?

src/lib/dotify-install.sh

@@ -6,5 +6,5 @@ dotify-install() {
   if [ -z "$target" ]; then return 1; fi
 
   parse-dotfile "$dotfile" "$target"
-  return "$?"
+  return $?
 }