Deprecate and remove wildcard output selection

[cameel]

Closes #14363.

Abstract

Deprecate the use of * to select multiple outputs in outputSelection in Standard JSON. Its use should result in a warning and it should eventually be removed.

We may want to replace it with a more descriptive mechanism (e.g. having some special names covering groups of related outputs). If we do keep *, it should return to its original meaning of "all outputs".

Motivation

Standard JSON allows using * to select multiple outputs:

"outputSelection": {
    "contract.sol": {
        "C": ["*"]
    }
}

This used to mean "all outputs", but this is no longer the case. Experimental and IR outputs (#14363) are excluded. The same will likely happen eventually with ethdebug outputs (#16460).

Even if it did mean "all outputs", its usefulness is questionable. For performance it's always better to pick as few outputs as possible. Having a convenient shortcut for this suggests that requesting them all is sometimes a valid option. This is really mostly the case for debugging/testing and should not be done in production. This fact should be documented (#15744), but the intuitiveness of the design should be considered too.

Backwards Compatibility

Deprecation and a warning would be non-breaking. Actual removal from Standard JSON might be not only be breaking but even impossible as the format is supposed to be stable even across breaking compiler versions.

[cameel]

We discussed this on the 2026-02-18 call. We decided to start issuing deprecation warnings for this and remove the feature eventually (possibly in 0.9, but this is lower priority than other tasks).