manual: add Clasp to "Implementation Support"
manual: add Clasp to "Implementation Support"

stassats/cffi,cffi/cffi,stassats/cffi,cffi/cffi,dkochmanski/cffi,cffi/cffi,3b/cffi,stassats/cffi,dkochmanski/cffi,3b/cffi,dkochmanski/cffi,3b/cffi