[sfnt] 'COLR' v1 PaintSweepGradient spec update

* src/sfnt/ttcolr.c (read_paint): PaintSweepGradient follows other
spec changes and now has the angles specified as F2DOT14, reflect
that in the implementation.
* include/freetype/ftcolor.h (FT_PaintSweepGradient): Update
documentation.
2 files changed