Alexander Gherm 798cc7bf3c Make more informative warning message when failed to parse pyproject.toml (#6009) ...

## Summary

Added the actual error message to the warning when uv fails to parse
`pyproject.toml`.

Resolves https://github.com/astral-sh/uv/issues/5934

## Test Plan

Took the case from the issue:
- have `pyproject.toml` which contains
```
[tool.uv]
foobar = false
```
- 
```
$ uv venv --preview -v
```
- Expect the message that contains the actual problem in the
`pyproject.toml` like:
```
warning: Failed to parse `pyproject.toml` during settings discovery: unknown field `foobar`; skipping...
```

2024-08-11 21:13:14 +00:00

..

src

Make more informative warning message when failed to parse pyproject.toml (#6009)

2024-08-11 21:13:14 +00:00

Cargo.toml

Make more informative warning message when failed to parse pyproject.toml (#6009)

2024-08-11 21:13:14 +00:00