Add match?-declaration in u-t.matcher-combinators

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Problem statement

match? is a multi-method dispatch symbol, not a function. So it misses highlighting and a proper refer.

This has a couple of caveats:

• lack of traceability. The assert-expr is registered when nedap.utils.test.matcher-combinators is loaded, which might be in a different ns
• formatters might remove [nedap.utils.test.matcher-combinators] as a dependency, if it is only loaded for registering the match?-matcher.

Proposal

add a declaration for the multimethod. Similar to matcher-combinators:
https://github.com/nubank/matcher-combinators/blob/b3da18923f0aa6a5ef924e9303f690a3efa1d978/src/cljc/matcher_combinators/test.cljc#L10-L11