Tools: HTML comments on templates are being used as element comments

[justinfagnani]

See the wonder comment here by @notwaldorf https://www.webcomponents.org/element/PolymerElements/paper-input/elements/paper-input

[notwaldorf]

Screenshot for posterity. The comment comes from: https://github.com/PolymerElements/paper-input/blob/master/paper-input.html#L165

[arthurevans]

As awesome as this comment is, can we make this a P0 or at least a P0.5 because it looks really, really bad is totally unhelpful to users.

[rictic]

Taking a look now.

[web-padawan]

might be related to #674, although comments outside of templatetag (e. g. between groups of HTML imports) are also treated like this.