Highlight Alternate Glyphs no longer drops a lam-alef cluster's glyphs
outright: the ligature is clear when required shaping, or shaping with
liga left on (older fonts), gives it, so an optional feature such as
salt that changes it is highlighted again. is_lam_alef takes any
combining mark by Unicode general category (Arabic Extended-A/B/C
included) instead of a partial list. The test font maps the fatha to a
mark and skips marks in its ligature, so the mark-spanning test checks
the exact ligature glyph and cluster; it gains a salt lookup and test.
Also a one-line equivalent nonminimal_bool repair in pathops'
pathtools that strict Clippy needs on main.
Highlight Alternate Glyphs compares each glyph with required shaping
alone, which turns liga and calt off. Older Arabic fonts (such as the
legacy Arial of the Microsoft core fonts) put the mandatory lam-alef
ligature in liga instead of rlig, so every lam-alef was highlighted.
A lam + alef cluster (any alef form, marks allowed) is now never an
alternate candidate, whatever feature the font uses.
Adds a test font built in code (lam-alef under liga or rlig) and
host-independent regressions. Also two equivalent one-line repairs
strict Clippy needs on main: a nonminimal_bool in the Path Precision
Tools inspect check and is_none() in a gradient panel test.
Don Omondi