General Registry: Create tag for macro usage

[mbauman]

Let’s consolidate this discussion over at the simultaneous Internals & Design post that’s also about how to handle registry submissions that export macros. This is more of an internals/governance sort of thing than it is New to Julia.

How to discourage macros: disable automerge of General registry PRs?

It seems to me that macros are defined much too often in the Julia ecosystem and the (error-prone) definitions of such macros are often very complex. FWIW, the Julia Manual page on metaprogramming already heavily discourages defining macros: eval and defining new macros should be typically used as a last resort. It seems to me that (almost?) the only good way to design a package that includes macros is like this: the macro simply provides some syntax sugar over an actual Julia function, w…