fix last modified not working for capitalized pages

layouts/_default/single.html

@@ -15,7 +15,7 @@
   <article>
       {{if .Title}}<h1>{{ .Title }}</h1>{{end}}
       <p class="meta">
-          Last updated {{ .Lastmod.Format "January 2, 2006" }}
+          Last updated {{if ne .Date .Lastmod}}{{ .Lastmod.Format "January 2, 2006" }}{{else}}Unknown{{end}}
       </p>
       {{if $.Site.Data.config.enableToc}}
       <aside class="mainTOC">