html Element is missing lang attribute

[kimberlythegeek]

Every HTML document should have a lang attribute. reference

[linuxwolf]

@kimberlythegeek I'm not versed enough in the lang attribute to know how this ought to interact with localization.

@jimporter I'm guessing we insert the lang based on the locale we negotiate through fluent-react?

[sandysage]

Let's consider this a discovery effort to determine what needs to happen here and then we can prioritize the scope of work from this.