Add tasks for all the new languages

Task/Literals-String/Sidef/literals-string-1.sidef

@@ -0,0 +1,4 @@
+'single quotes with \'embedded quote\' and \\backslash';
+‚unicode single quoted’;
+%q(not interpolating with (nested) parentheses
+and newline);

Task/Literals-String/Sidef/literals-string-2.sidef

@@ -0,0 +1,4 @@
+var a = 42;
+"double \Uquotes\E with \"embedded quote\"\nnewline and variable interpolation: #{a} % 10 = #{a % 10}";
+„same as above”;
+%Q(same as above);

Task/Literals-String/Sidef/literals-string-3.sidef

@@ -0,0 +1,13 @@
+print <<EOT
+Implicit double-quoted (interpolates):
+a = #{a}
+EOT
+
+print <<"EOD"
+Explicit double-quoted with interpolation:
+a = #{a}
+EOD
+
+print <<'NON_INTERPOLATING'
+This will not interpolate: #{a}
+NON_INTERPOLATING