vim: Add support for vim::PreviousLineStart motion (#14193)

Release Notes:

- vim: Added `-`/`+` to go to beginning of line above/below
([#14183](https://github.com/zed-industries/zed/issues/14183)).
- vim: (Breaking) Removed non-standard builtin binding from `-` to open
the project panel. You can re-add it to your keymap file with:
`{"context":"VimControl", "bindings":{ "-":
"pane::RevealInProjectPanel"}}`


Optionally, include screenshots / media showcasing your addition that
can be included in the release notes.


https://github.com/zed-industries/zed/assets/32429059/0e9e9348-265e-4a81-a45a-4739034dc5d9

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Co-authored-by: Conrad Irwin <conrad.irwin@gmail.com>