This commit fixes the malformed comment that would sometimes comment out
the rest of the html resulting in an improper display.
this is due to the new html5 notation --!> not behing understood by
our parser.
this commit replaces any --!> into -->.
this commit also remove <!--> or <!--->
opw-2812488
closesodoo/odoo#126148
X-original-commit: 4fed0c36fedf271acc3520d8219763964753dabe
Signed-off-by: Vranckx Florian (flvr) <flvr@odoo.com>