Follow cl-ft2 e574516: the argument types are exported
The API index lists the twelve types cl-ft2 now exports, and the page
of each says which values make it up: font-source on Library and faces,
encoding and character-or-code on Character maps, hinting-target and
kerning-mode on Glyphs and metrics, render-mode, pixel-mode and
pixel-data on Rendering and bitmaps, line-cap, line-join and
stroke-border on Glyph objects and strokers, and fill-rule on Outlines.
