feat: Nice errors for shim flag parsing (#6737)
### Description
This adds nice errors for shim parsing:
<img width="272" alt="Screenshot 2023-12-07 at 5 31 42 PM"
src="https://github.com/vercel/turbo/assets/7357863/a225b365-32b2-45c7-8a06-b921530537d9">
<img width="582" alt="Screenshot 2023-12-07 at 5 38 17 PM"
src="https://github.com/vercel/turbo/assets/7357863/a9e125b1-5ac2-4889-822c-50b681d62299">
### Testing Instructions
Added test for error output
Closes TURBO-1874
---------
Co-authored-by: nicholaslyang <Nicholas Yang>
Co-authored-by: Chris Olszewski <chris.olszewski@vercel.com>
