Fix URL next to description of the project

[tripu]

I guess the “website” field that is shown on the front page of the repo, at the top, should be either
https://w3c.github.io/speech-api/webspeechapi.html
or
https://w3c.github.io/speech-api/speechapi.html
?

[foolip]

Yeah, I used the URL that I think we should use, hoping nobody would notice until we have something there. I'll fix it and change it back later.