feature request: add plot grade to output

[m4chinations]

hey, really appreciate the plugin, it's helping a lot of people!

i would love for the output string (or as a custom output option) to include the plot grade. grade is just a static map of plot number to grade 1-5, the grades are shown here: https://imgur.com/a/n7wzC

helpful for people wanting to upgrade to a more desirable plot since grade is a good measure of desirability.