You can now put `||` between two fix-its to indicate that the test succeeds if either of them is present. This is meant for situations where a fix-it might vary slightly in different subtests or test configurations.
Also fixes a bug in the diagnostic verifier where "expected-whatever" would search beyond the same line for its opening "{{", potentially finding one many lines away and giving a bad diagnostic and poor recovery behavior.
If, for instance, an error is emitted as a warning instead, the verifier now detects this and emits a single diagnostic saying that the warning was found but had the wrong kind, instead of emitting one diagnostic saying the error was missing and another saying the warning was unexpected.
In theory there are some edge cases we could handle better by doing two separate passes—one to detect exact expectation matches and remove them, another to detect near-misses and diagnose them—but in practice, I think the text + diagnostic location is likely to be unique enough to keep this from being a problem. (I would hesitate to do wrong-line diagnostics in the same pass like this, though.)
A header shouldn't contain a function body unless the function is
inline. Following gribozavr's suggestion, I'm using the easier solution
of omitting the semicolon from the function prototype.
(In response to review comments.)
