Have markdown-do do markdown-cleanup-list-numbers

[hmelman]

I only recently realized about markdown-do and recently had trouble finding the binding for markdown-cleanup-list-numbers (I didn't remember the name and searched for "renumber", "fix", and "order" before looking at the menu). Could markdown-do when point is on an ordered list number do markdown-cleanup-list-numbers?

Currently it seems to add a gfm checkbox after the number. I think having it do markdown-cleanup-list-numbers would be more in line with its current behavior of doing markdown-table-align in a table.