Remove unneeded XML-isms

&lt;link&gt; tags assume text/css if 'type' isn't specified:
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/style

&lt;script&gt; tags are assumed to be javascript if no 'type' is specified:
https://developer.mozilla.org/en-US/docs/Web/HTML/Element/script

Self-closing tags in html don't need the trailing slash.

The doctype says this is HTML, so we don't need to add XML attributes to
the &lt;html&gt; tag.