Add --pass-with-no-tests option

[whitneyit]

This PR adds a --pass-with-no-tests option.

This allows for parity with vitest's --passWithNoTests and jest's --passWithNoTests options.

[mrazauskas]

Just use directory option to point tsd to any exiting directory.

In package.json you should add:

"tsd": {
  "directory": "src"
}

and tsd will pass without tests.

---

Or simply try: npx tsd --files .

[whitneyit]

I understand those approaches exist. However, those workarounds do not address the use case that this type of flag is commonly intended for.