added post failure screen

templates/comment_post_failed.tmpl

@@ -0,0 +1,11 @@
+{{ template "header.tmpl" . }}
+		<h2>Your comment <u>failed</u> to be posted...</h2>
+		<p>You will be redirected or, click <a href="/blog/post/{{ .Url }}">here</a> to return to the blog post.</p>
+		<input value="{{ .Url }}" readonly style="display: none;" id="url"/>
+		<script>
+			setTimeout(() => {
+				window.location.replace("/blog/post/" + document.getElementById("url").value)
+			}, 1500)
+		</script>
+	</body>
+</html>