Support `clang::annotated` style annotation parsing via ast_canopy

[isVoid]

Example code:

[[ clang::annotate("numbast::TestAttr") ]]
double carrot([[clang::annotate("numbast::StatefulOperator")]] [[maybe_unused]] double num);

struct [[clang::annotate("aligned")]] Foo {
    [[clang::annotate("depracated")]] int bar;
};

Expected Result:

Declaration should contain a new attribute named annotations which contains a list of annotation strings.

Applicable to function, function paramDecls, struct decls and members.