change --html to make sure we use the HTML serialization rule by default

* xmllint.c: change --html to make sure we use the HTML serialization
  rule by default when HTML parser is used, add --xmlout to allow to
  force the XML serializer on HTML.
* HTMLtree.c: ugly tweak to fix the output on <p> element and
  solve #125093
* result/HTML/*: this changes the output of some tests
Daniel
6 files changed