Drop 'autoescape' from Soy template example

Soy templates no longer support the autoescape parameter. So compiling
the example template failed with

  Unsupported attribute 'autoescape' for 'template' tag, expected one of [visibility, kind, requirecss, cssbase, stricthtml, whitespace].

So we drop the autoescaping from the example, as strict autoescaping is
the default anyways according to

  https://github.com/google/closure-templates/commit/7ec73614d32ff72acb22c64b0841362b06f9d1bf

Change-Id: I4e2dc440041358759e6d8b789747c1fd15ab1983