Add canonical to 5ftf pages

[iandunn]

Copied from https://meta.trac.wordpress.org/ticket/4822

Right now, these three are different pages to Google and other search engines:

• https://wordpress.org/five-for-the-future/pledges/
• https://wordpress.org/five-for-the-future/pledges/?order=alphabetical
• https://wordpress.org/five-for-the-future/pledges/?order=hours

Whereas in reality they don't differ that much at all. So let's add a canonical to that page, like so:

Independent of which sort order is used.

[jdevalk]

Commenting, available for followup questions if needed :)

[iandunn]

It looks like the pledges ones have been handled by wporg-seo.

#142 mentioned this one as well:

https://wordpress.org/five-for-the-future/?s=yoast should omit the tag

...which now has https://wordpress.org/five-for-the-future/search/yoast/ as the canonical. Is it preferable to have no tag at all on that page @jonoalderson ?

[jonoalderson]

Yep, as a noindex'd page, that should omit the tag.