fix(_quote_readline_by_ref): unescape escape sequences using printf

Author: akinomyoga

bash_completion

@@ -554,7 +554,8 @@ _quote_readline_by_ref()
         if [[ ${!2} == \$\'*\' ]]; then
             local value=${!2:2:-1}      # Strip beginning $' and ending '.
             value=${value//'%'/%%}      # Escape % for printf format.
-            printf -v value %s "$value" # Decode escape sequences of \....
+            # shellcheck disable=SC2059
+            printf -v value "$value"    # Decode escape sequences of \....
             local "$2" && _upvars -v "$2" "$value"
         fi
     fi