Only use outside border of stroke in text()

[radarhere]

Resolves #8697

The issue finds that when Pillow draws normal text onto stroked text, there might be an unexpected gap between the the outside of the normal text and the inside border of the stroked text.

When drawing stroked text, FreeType returns a glyph with an outside border and an inside border. We can ask FreeType to leave out the inside border though, creating a filled glyph. With that change, the output is corrected.

See https://freetype.org/freetype2/docs/reference/ft2-glyph_stroker.html#ft_glyph_stroke and https://freetype.org/freetype2/docs/reference/ft2-glyph_stroker.html#ft_glyph_strokeborder for documentation.

[apodtele]

Using only outside border is a good solution in this case.. You might try faster FT_Outline_EmboldenXY but it does not have round joints.

The algorithms are rather complicated. I suspect the problem with the inside border arises when the stroker radius exceeds the stem width or the dot radius. The inside border is ill-defined in this case. I doubt this can be fixed. This could happen to the outside border too but much less frequently.

[radarhere]

Thanks very much for your input.