misc(treemap): add locale to html tag

[coliff]

Summary

This fixes #12730

The page is missing lang="en" attribute. When loading page in Edge it offered to translate the page from Maltese to English for me. Specifying the lang will tell the browser it's in English already.

Related Issues/PRs

[adamraine]

This would fix the problem for english users and the landing page, but we do have some translated strings in the treemap. I'm thinking we have a default value of en-US and programmatically change it when we get the locale:

Basically just stick a

document.documentElement.lang = options.lhr.configSettings.locale

in here

lighthouse/lighthouse-treemap/app/src/main.js

Lines 760 to 768 in 8bb2f21

	/**
	* @param {LH.Treemap.Options} options
	*/
	init(options) {
	TreemapUtil.find('.treemap-placeholder').classList.add('hidden');
	TreemapUtil.find('main').classList.remove('hidden');
	const i18n = new I18n(options.lhr.configSettings.locale, {
	// Set missing renderer strings to default (english) values.

@connorjclark would this work?

Additional ref #12647

[adamraine]

@coliff do you still want this?

[coliff]

I'm not 100% certain of exactly where that document.documentElement.lang = options.lhr.configSettings.locale goes in the main.js so if someone else could kindly take care of that then that'd be awesome.

[adamraine]

Closing in favor of #13454. I'll add you as a co-author.