Follow cl-harfbuzz c2314ad: tag and script are exported
The API index lists the types tag and script, Core concepts names them
in its table of representations, Shaping names script among the buffer
properties and Faces names tag for face-table. Installation adds the
names a package that uses cl-harfbuzz must shadow: tag with both raw
layers, whose struct slots have that name, and script with sb-unicode.
Development counts 402 checks.
