handout: Allow customising document language

latex/common/handout.cls

@@ -1,11 +1,20 @@
 % vim: set ft=tex
+\RequirePackage{kvoptions}
+\SetupKeyvalOptions{
+ family = handout,
+ prefix = handout@,
+}
+
+\DeclareStringOption[ngerman]{language}
+\ProcessKeyvalOptions{handout}
+
 \LoadClass[
  DIV=20,
  parskip=half,
 ]{scrartcl}
 
 % hyphenation
-\RequirePackage[ngerman]{babel}
+\RequirePackage[\handout@language]{babel}
 
 % cretion of nice dates from numbers
 \RequirePackage[useregional]{datetime2}