The indentation stripping semantics of strings are fairly bad and have a
few gotchas where they behave unintuitively. But the good news is, that
these cases are easy to catch and can be avoided.
This commit adds a warning in the parser when such strings are detected.
Unfortunately Nixpkgs uses this kind of a lot, so we won't be able to
actually enable this warning for a while to come.
Co-authored-by: Commentator2.0 <lix@crystal-cavern.systems>
Change-Id: I3b3b68c2eee4cd70959d3f4ca643cb6caf3a2217
