Rename `filter_deleted` to `reject_deleted`

[chadoh]

Hello! Loving this plugin 😄

Since filter is a neutral word that could mean "filter for" or "filter out", what do you think of renaming this method to reject_deleted? A corresponding filter could be select_deleted.

[fsaravia]

@chadoh thanks! That's a great idea and thank you for helping me improve my English-fu.

I would like to keep a reference to filter_deleted for backwards compatibility reasons but I agree that renaming the original method will be helpful. I can work on this as soon as I have some bandwidth but PRs are always welcome!