Simplify XML escaping

Change-Id: I3fd94e10e48fee71ab5a7f0e82f6540ab50d0f54
diff --git a/lib/KorAP/XML/TEI.pm b/lib/KorAP/XML/TEI.pm
index 8f1678d..d616461 100644
--- a/lib/KorAP/XML/TEI.pm
+++ b/lib/KorAP/XML/TEI.pm
@@ -70,17 +70,13 @@
 
 # Escape strings using XML entities
 sub escape_xml {
-  my $data = shift // '';
-  $data =~ s/([&<>"])/$ent{$1}/ge;
-  return $data;
+  ($_[0] // '') =~ s/([&<>"])/$ent{$1}/ger;
 };
 
 
 # Escape
 sub escape_xml_minimal {
-  my $data = shift // '';
-  $data =~ s/([&<>])/$ent_without_quot{$1}/ge;
-  return $data;
+  ($_[0] // '') =~ s/([&<>])/$ent_without_quot{$1}/ger;
 };