Normally, an end tag for a void element would simply be discarded,
but the spec includes a special rule as follows:
An end tag whose tag name is "br"
Parse error. Drop the attributes from the token, and act as
described in the next entry; i.e. act as if this was a "br"
start tag token with no attributes, rather than the end tag
token that it actually is.
Normally, an end tag for a void element would simply be discarded, but the spec includes a special rule as follows:
closes https://github.com/Masterminds/html5-php/issues/185