Twenty Fifteen: class="says" has style defined as display: none, should be like screen-reader-only

[rianrietveld]

In wp-includes/comment-template.php the class="says" is added to hide text from screen.

Twenty Fifteen defines that as

.says {
	display: none;
}

Display: none; also hides text from screen readers, so it's not useful to do so.

It would be better if that was defined as or like screen-reader-text.

Is there a way to solve this like @mattwiebe did in #30110?

[iamtakashi]

Or apply .says the same style as .screen-reader-text ?

[iandstewart]

a11y-ready hiding of "says:" in comments

[iandstewart]

@davidakennedy did a quick review of the above. Looks good. Committing.

[iandstewart]

In 30570:

Twenty Fifteen: make sure the 'says:' in comments is readable by a screen-reader.

Fixes #30479.