:History file path generation breaks when autochdir enabled

- Category
- [x] Question
- [X] Bug
- [ ] Suggestion
- OS
- [X] Linux
- [ ] macOS
- [ ] Windows
- [ ] Etc.
- Vim
- [ ] Vim
- [X] Neovim
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FZF is *amazing* thank you so much for all your hard work, really impressive work :)

When using `:History` with `autochdir` enabled the suggested paths are incorrect. Once I enable it all the suggestions become relative to the currently opened file, but when selecting one of those options the opened file isn't right.

Here are the repro steps
* `mkdir -p foo/`
* `echo 'this is my a file' > foo/a && echo 'this is my b file' > foo/b`
* Open `a` and `b` in vim so they are in your history
* Load the minimal vim config, and `set autochdir`
* Load the `a` file via `:History` now try to load the `b` file via `:History` it will actually open `./b` and not `./foo/b`