misc(seo) add canonical to the pages html, use trailing slash for con…

[EugeneHlushko]

• adds canonical
• adds trailing slash to it to be consistent with how github pages serve
• Fixes Installation page is broken, 404 Not Found #2992

Update on sitemap, this is before:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    <url>
        <loc>https://webpack.js.org/index.html</loc>
    </url>
    <url>
        <loc>https://webpack.js.org/api/index.html</loc>
    </url>
    ...

And now it is:

<?xml version="1.0" encoding="UTF-8"?>
<urlset xmlns="http://www.sitemaps.org/schemas/sitemap/0.9">
    <url>
        <loc>https://webpack.js.org</loc>
    </url>
    <url>
        <loc>https://webpack.js.org/api</loc>
    </url>
    ...

[netlify]

Preview is ready

Built with commit 5e2977a

https://deploy-preview-2999--webpackjsorg-netlify.netlify.com

[EugeneHlushko]

@montogeek i found the root cause of this in analytics, will fix tonight.

Ready for review

[montogeek]

Nice find!