Fix fi & ffi glyph widths to match non-ligated sequences; set other ligatures to non-exporting glyphs #431
Description
Problem description
In Sans Linear Light Italic, the fi ligature is a different width than f + i (800 vs 750). For fl, the width is different from f + l across all Sans styles.
It is likely that this discrepancy may exist in other ligatures, like ffl and ffi. It should be fixes.
Expected behavior
Recursive Sans is meant to be superplexed/multiplexed – words should have the exact same width regardless of weight or style. So, a word like "fly" should be exactly the same width whether upright or slanted. Currently, it is just slightly wider when slanted, because the slant axis activates the fl ligature.
Additional Context
There is already a script to check for widths of glyphs being the same across sources (permalink). I will likely start from this in the ligature check.