Trivial reformatting of entity files to emphasize usernames

Reformats entity files to put username attribute on own line thereby visually separating it from XML namespace declaration boilerplate.

This is followup on my tripping over not noticing the username attribute and thinking username was implied by entity filename in creating a new fragment-layout entity file by duplicating an existing such file.  Reformatting visually emphasizes the username attribute, which will differ across entity files, separating it from the boilerplate, which will not.