update backslash unit tests

spec/_files/backslashes.mustache

@@ -1,3 +1,7 @@
 * {{value}}
 * {{{value}}}
 * {{&value}}
+<script>
+foo = { bar: 'abc\"xyz\"' };
+foo = { bar: 'x\'y' };
+</script>

spec/_files/backslashes.txt

@@ -1,3 +1,7 @@
 * \abc
 * \abc
 * \abc
+<script>
+foo = { bar: 'abc\"xyz\"' };
+foo = { bar: 'x\'y' };
+</script>