Cannot use multiple #[stub_verified(..)] attributes to a single harness

[ShoyuVanilla]

The docs says

kani/library/kani_macros/src/lib.rs

Lines 368 to 375 in 7913e3c

	/// You may use multiple `stub_verified` attributes on a single harness.
	///
	/// This is part of the function contract API, for more general information see
	/// the [module-level documentation](../kani/contracts/index.html).
	#[proc_macro_attribute]
	pub fn stub_verified(attr: TokenStream, item: TokenStream) -> TokenStream {
	attr_impl::stub_verified(attr, item)
	}

but actually, we can't because

kani/kani-compiler/src/kani_middle/attributes.rs

Lines 373 to 375 in 7913e3c

	KaniAttributeKind::StubVerified => {
	expect_single(self.tcx, kind, &attrs);
	}

I'd like to fix this but I wonder which way it was originally intended for.