fix: extractTeXpatterns
fix: extractTeXpatterns

Problem: if a char doesn't have an uppercase representation
it's lowercase representation is written to the chr file.
Looks like this behaviour has changed (before nothing was output).

Solution: return "" if lc===uc

[ci skip]

mnater/Hyphenopoly,mnater/Hyphenopoly,mnater/Hyphenopoly,mnater/Hyphenopoly