Capability System: Redesign how failed capabilities on EntryPoints<->compileTarget are described to a user

[ArielG-NV]

Currently in the capabilities system, erroring once we reach a stage of checking EntryPoints<->compileTarget (Diagnostics::entryPointUsesUnavailableCapability) produces assumptions of what went wrong.

These assumptions assumes based on providence of a single Decl that any incompatible capability may be the problem. This erroring works well when the problem is straight-forward or the function has little capabilities defined. When the problem is within a function with many overlapping capabilities the current "providence" tracking provides little assistance in erroring due to only tracking a single "providence".

One solution to this would be to redesign the approach to store UIntSets of callee and parent functions that remove a target

• It would be faster to save debug data but slower to emit debug information.