Hi,

in LuaTeX node.ligaturing should return the head and the tail of the
list after ligatures got applied. But in the case that the tail of the new
list is a discretionary the current code returns the passed in tail
instead, assuming that it didn't change. This breaks if the
discretionary node wasn't the tail before the ligature pass:.

r65175 | lscarso | 2022-12-03 12:53:48 +0100 (Sat, 03 Dec 2022) | 1 line
Changed paths:
   M /trunk/Build/source/texk/web2c/luatexdir/ChangeLog
   M /trunk/Build/source/texk/web2c/luatexdir/font/luafont.c
   M /trunk/Build/source/texk/web2c/luatexdir/luatex_svnversion.h

Track last node in ligature handling (M.Krüger)
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