Dyno error for variable without init/type, split-init error notes

[arezaii]

This converts some parts of dyno's NoMatchingCandidates error to mention bad split-init as the cause in the summary view of the error, instead of only in the details.

This also adds a new error when a variable has no type or init component.

[arezaii]

I ran the suite of spec tests against this and found no changes to which tests passed or failed compared to main.

Test Failures

[Error matching compiler output for release/examples/primers/LinearAlgebralib]
[Error matching compiler output for release/examples/primers/arrays]
[Error matching compiler output for release/examples/primers/associative]
[Error matching compiler output for release/examples/primers/distributions]
[Error matching compiler output for release/examples/primers/domains]
[Error matching compiler output for release/examples/primers/fileIO]
[Error matching compiler output for release/examples/primers/interopWithC]
[Error matching compiler output for release/examples/primers/learnChapelInYMinutes]
[Error matching compiler output for release/examples/primers/loops]
[Error matching compiler output for release/examples/primers/procedures]
[Error matching compiler output for release/examples/primers/reductions]
[Error matching compiler output for release/examples/primers/replicated]
[Error matching compiler output for release/examples/primers/slices]
[Error matching compiler output for release/examples/primers/sparse]
[Error matching compiler output for release/examples/primers/specialMethods]
[Error matching compiler output for release/examples/primers/timers]
[Error matching compiler output for release/examples/primers/chplvis/chplvis2]
[Error matching compiler output for release/examples/primers/chplvis/chplvis3]
[Error matching compiler output for release/examples/primers/chplvis/chplvis4]
[Error matching compiler output for release/examples/spec/Arrays/adecl-assocLiteral]
[Error matching compiler output for release/examples/spec/Arrays/slicing]
[Error matching compiler output for release/examples/spec/Classes/fieldsOutOfOrder]
[Error matching compiler output for release/examples/spec/Classes/usedBeforeInitialized]
[Error matching compiler output for release/examples/spec/Generics/compilerDiagnostics]
[Error matching compiler output for release/examples/spec/Generics/partially-concrete-tuple-ambiguity]
[Error matching compiler output for release/examples/spec/Modules/ambiguity]
[Error matching compiler output for release/examples/spec/Tuples/aliasing]
[Error matching compiler output for release/examples/spec/Tuples/omit-component]
[Error matching compiler output for release/examples/spec/Variables/no-split-init]