Remove @testable imports, upgrading symbols to public visibility.

[dylansturg]

No description provided.

[allevato]

Since we have to sacrifice access control now, please add a leading underscore to this function name so that it doesn't leak (as obviously) into the SwiftFormat public API. (IIRC, SourceKit may have some logic that excludes or deprioritizes declarations with leading underscores from code complete suggestions.)

[akyrtzi]

SourceKit may have some logic that excludes or deprioritizes declarations with leading underscores from code complete suggestions

I think this is only for system frameworks but @rintaro will know for sure.

[dylansturg]

I think Argyrios is right - code complete is still suggesting _firstInvalidSyntaxPosition as the first option when I type something similar with other alternatives. I tried inside-of this module and in other modules (specifically the relevant test case).

I think a leading underscore still provides a hint to avoid using this function.

Alternatively, I could use an enum to add a namespace around this function (e.g. SwiftFormatInternal). Let me know if you think we should try harder to hide it.

[rintaro]

Yeah, hiding _ prefixed symbols are for system frameworks only.

[allevato]

Ah, bummer. Well, this is fine for now—the leading underscore should be enough of an indicator that it should be hands-off. We can consider cleaning it up later if we feel there's a larger need.

Thanks for clarifying, @akyrtzi and @rintaro !