update elements and fix some bugs

lib/src/prism/tests/languages/objectivec/string_feature.test

Index: lib/src/prism/tests/languages/objectivec/string_feature.test
diff --git a/lib/src/prism/tests/languages/objectivec/string_feature.test b/lib/src/prism/tests/languages/objectivec/string_feature.test
new file mode 100644
index 0000000000000000000000000000000000000000..d6c7b30da070cbaf9cbadb0bd7cc615c06995569
--- /dev/null
+++ b/lib/src/prism/tests/languages/objectivec/string_feature.test
@@ -0,0 +1,34 @@
+""
+"fo\"o"
+"foo\
+bar"
+
+''
+'fo\'o'
+'foo\
+bar'
+
+@""
+@"fo\"o"
+@"foo\
+bar"
+
+----------------------------------------------------
+
+[
+	["string", "\"\""],
+	["string", "\"fo\\\"o\""],
+	["string", "\"foo\\\r\nbar\""],
+
+	["string", "''"],
+	["string", "'fo\\'o'"],
+	["string", "'foo\\\r\nbar'"],
+
+	["string", "@\"\""],
+	["string", "@\"fo\\\"o\""],
+	["string", "@\"foo\\\r\nbar\""]
+]
+
+----------------------------------------------------
+
+Checks for strings.