Speech Synth: inputs don't have labels

[dstorey]

There are a couple of mistakes that lead to the text fields not having labels:

• The voice, volume, and rate labels use a for attribute with a prefixless ID (correct), but the actual form fields have IDs with "js-" prefix (incorrect as ID isn't just for JS). Fix here is to remove the js- prefix from the IDs and change the JS to hook into those new IDs.

• The initial text to speech input doesn't have a label. It would be better to have a visible label to make it more obvious what it is. If that can't work then add a placeholder attribute and an aria-label attribute.