Use babel options shorthands=off.

This has been fixed now in Babel for some time.  So we can now
get rid of the ugly code that disabled language-specific shorthands
(see e26d31d).

Closes #6817.

data/templates/common.latex

@@ -183,9 +183,9 @@ $-- Babel language support
 $--
 $if(lang)$
 \ifLuaTeX
-\usepackage[bidi=basic$for(babeloptions)$,$babeloptions$$endfor$]{babel}
+\usepackage[bidi=basic,shorthands=off,$for(babeloptions)$,$babeloptions$$endfor$]{babel}
 \else
-\usepackage[bidi=default$for(babeloptions)$,$babeloptions$$endfor$]{babel}
+\usepackage[bidi=default,shorthands=off,$for(babeloptions)$,$babeloptions$$endfor$]{babel}
 \fi
 $if(babel-lang)$
 $if(mainfont)$
@@ -198,9 +198,6 @@ $endif$
 $for(babelfonts/pairs)$
 \babelfont[$babelfonts.key$]{rm}{$babelfonts.value$}
 $endfor$
-% get rid of language-specific shorthands (see #6817):
-\let\LanguageShortHands\languageshorthands
-\def\languageshorthands#1{}
 \ifLuaTeX
   \usepackage{selnolig} % disable illegal ligatures
 \fi