Add requireIsAnnotatable for better errors when annotating literals (backport #3968) (#3970)

* Add requireIsAnnotatable for better errors when annotating literals (#3968)

(cherry picked from commit 4be3b6fb

)

# Conflicts:
#	core/src/main/scala/chisel3/dontTouch.scala
#	src/test/scala/chiselTests/DontTouchSpec.scala

* Resolve backport conflicts

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Co-authored-by: Jack Koenig <koenig@sifive.com>