build: fix annotations for BuildTarget.link*target
build: fix annotations for BuildTarget.link*target

which do not hold BuildTargets, they are `SharedLibrary | StaticLibrary |
CustomTarget | CustomTargetIndex` (whole doesn't accept `SharedLIbrary`)

pexip/meson,pexip/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson,pexip/meson,pexip/meson,mesonbuild/meson,mesonbuild/meson,pexip/meson