support syntax macro OtherPackage.theirmacro(args...) ... end

[schlichtanders]

As a outcome from this discourse issue https://discourse.julialang.org/t/how-to-define-a-macro-via-package-extension/114218/5
I want to open an issue to track that the syntax to extend functions and macros do not match.

While extending functions and macros works the same when importing them (like import OtherPackage: @theirmacro), using qualified definitions only works for functions.

works:

function OtherPackage.theirfunction(args...)
    # works
end

doesn't work:

macro OtherPackage.theirmacro(args...)
    # fails with `ERROR: syntax: invalid macro definition ...`
end

As the functionality of extending is already support for both, it would be great if also the syntax support is consistent.