Help With: “Spaces should be escaped as .”

I’ve recently switched my WP to HTML5.

With the new validation, it’s giving me some new issues.

Take a look at this page for instance:
https://validator.w3.org/check?uri=http%3A%2F%2Fskattertech.com%2F2009%2F11%2Fironkey-s200-review%2F&charset=%28detect+automatically%29&doctype=Inline&group=0

It is asking to do “Spaces should be escaped as %20.” I know the issue is placing the the_title(); in a URL. It’s not encoding properly, but works. With PHP or a WP function, how can I have it properly encode that?

Any help or a point in the right direction would be helpful. Thanks!