Merge pull request freeCodeCamp#12584 from Manish-Giri/fix/assert-uni…

…que-h1-element

Add test to assert single h1 element

seed/challenges/01-front-end-development-certification/html5-and-css.json

@@ -4489,6 +4489,7 @@
         "assert($(\"h1\").hasClass(\"pink-text\"), 'message: Your <code>h1</code> element should have the class <code>pink-text</code>.');",
         "assert($(\"h1\").hasClass(\"blue-text\"), 'message: Your <code>h1</code> element should have the class <code>blue-text</code>.');",
         "assert($(\"h1\").attr(\"id\") === \"orange-text\", 'message: Give your <code>h1</code> element the id of <code>orange-text</code>.');",
+        "assert(($(\"h1\").length === 1), 'message: There should be only one <code>h1</code> element.');",
         "assert(code.match(/#orange-text\\s*{/gi), 'message: Create a CSS declaration for your <code>orange-text</code> id');",
         "assert(!code.match(/<h1.*style.*>/gi), 'message: Do not give your <code>h1</code> any <code>style</code> attributes.');",
         "assert($(\"h1\").css(\"color\") === \"rgb(255, 165, 0)\", 'message: Your <code>h1</code> element should be orange.');"