fix mistake in tex2lyx testfile

- XeTeX-polyglossia.tex: Hebrew is used in the file and so it must be declared

src/tex2lyx/test/XeTeX-polyglossia.tex

@@ -8,7 +8,7 @@
 \setdefaultlanguage[variant=british, ordinalmonthday = false]{english}
 \setotherlanguage{albanian}
 \setotherlanguage[variant=polytonic]{greek}
-\setotherlanguage{syriac}
+\setotherlanguage{hebrew}
 \begin{document}
 
 \part{df}