Replaced <br/> with <br>

[iainbeeston]

In regular HTML <br> is a void element, so it doesn't
need a closing tag or a closing slash. See the WhatWG
spec here: https://html.spec.whatwg.org/multipage/text-level-semantics.html#the-br-element

Many of the shared templates used by devise use <br/>
to separate lines. To make that more correct I've replaced
them with <br> instead.

[p8]

Hi @iainbeeston, 👋
Looking at that WhatWG spec it also recommends using paragraphs instead of a <br> for separating label and input.
That's how it used to be before: b86c1c2
Not sure if we should change that back as well.

[iainbeeston]

@p8 Thanks, I've replaced those with paragraph tags now. I've also updated the commit message to explicitly say that this reverts b86c1c2. Could you please take another look? (Especially at the HTML changes because I did them manually and it would be easy for me to make a mistake)