SharedHeaderBlock: Inline unnecessary format value

mentoring/header.py

@@ -47,8 +47,7 @@ class SharedHeaderBlock(LightChild):
         return block
 
     def student_view(self, context=None):
-        return Fragment(u"<script type='text/template' id='{}'>\n{}\n</script>".format(
-            'light-child-template',
+        return Fragment(u"<script type='text/template' id='light-child-template'>\n{}\n</script>".format(
             self.content
         ))