vim: Fix back quotes not recognized as object (#24999)

Currently back quotes ``` `` ``` not recognized as an object in vim
mode, so ```c i ` ```, ```d i ` ``` not working.

It seems to be a typo introduced in #22632 : The`DoubleQuotes` line was
doubled while the `BackQuotes` line was missing.

Release Notes:

- vim: Fixed back quotes ``` `` ``` not recognized as object.

Co-authored-by: Marshall Bowers <git@maxdeviant.com>