langref: fix unclosed and lonely tag

[Techatrix]

Previously the number of <p> and </p> where not the same.
Line 5588 has no closing tag and there is a lone tag on line 9414.

[andrewrk]

The CI runs tidy on the lang ref, we should figure out why this wasn't caught by it

[tato]

it might assume it was intentional

A p element's end tag may be omitted if the p element is immediately followed by an address, article, aside, blockquote, details, div, dl, fieldset, figcaption, figure, footer, form, h1, h2, h3, h4, h5, h6, header, hgroup, hr, main, menu, nav, ol, p, pre, section, table, or ul element, or if there is no more content in the parent element and the parent element is an HTML element that is not an a, audio, del, ins, map, noscript, or video element, or an autonomous custom element.

https://html.spec.whatwg.org/multipage/syntax.html#syntax-tag-omission