Formatter deletes all code after certain syntax errors

Nobody has claimed this yet.

### How are you using the lua-language-server?

Visual Studio Code Extension (sumneko.lua)

### Which OS are you using?

Windows

### What is the issue affecting?

Formatting

### Expected Behaviour

Code to be formatted without the rest of the code being deleted.

### Actual Behaviour

On certain errors, the formatter seems to delete everything past the point of error (though it occasionally saves a few lines).

https://user-images.githubusercontent.com/39929480/218354165-e1ea3e06-8bfe-49e0-a1dc-5709738d6721.mp4

### Reproduction steps

1. Create a test lua file
2. Write some lua code
3. At the very top, write `anything = ....` (I noticed just `anything =` will also cause issues)
4. Trigger a format run.
5. Watch your code disappear.

### Additional Notes

I'm not sure of all the errors that will trigger code deletion, but the ones I am aware of is:

- `anything = ....`
- `anything =`
- `anything = {x =}`

So my initial assumption is that it just affects errors with assignments.

### Log File

[file_d%3A_test%20directory.log](https://github.com/LuaLS/lua-language-server/files/10718039/file_d.3A_test.20directory.log)

Start by reproducing the problem with the malformed assignments listed in the issue and inspect the attached log file. Trace the formatting path for syntax-error input; done means formatting preserves all code after the error while still applying formatting where possible.

Written by the indexing model from the issue text.