#153, Remove extra spaces in generated tabs html

layouts/shortcodes/tabs.html

@@ -3,7 +3,7 @@
 {{ $group := printf "tabs-%s" $id }}
 
 <div class="book-tabs">
-{{ range $index, $tab :=  .Scratch.Get $group }}
+{{- range $index, $tab :=  .Scratch.Get $group -}}
   <input type="radio" class="hidden" name="{{ $group }}" id="{{ printf "%s-%d" $group $index }}" {{ if not $index }}checked="checked"{{ end }} />
   <label for="{{ printf "%s-%d" $group $index }}">
     {{ $tab.Name }}
@@ -11,5 +11,5 @@
   <div class="book-tabs-content markdown-inner">
     {{ .Content | markdownify }}
   </div>
-{{ end }}
+{{- end -}}
 </div>