don't put edit links on sections from included templates.

don't put edit links on sections from included templates.
template section headings have __MWTEMPLATESECTION__ added to them;
formatHeadings removes this and doesn't add the edit link for
such sections.  this is a rather hackish fix, but is probably
the best we can do with the current parser setup.

it would be nice (but not important) if this could be extended to
let users prevent edit links for certain sections.

fixes bug #266