[BUG] outdated download names in First Step

[jhdeov]

On the First Step's page, the Examples are telling us to download things that don't seem to exist anymore (english, mandarin_pinyin_g2)

For example in Example 2, I get the following error:

% mfa model download g2p mandarin_pinyin_g2p RemoteModelNotFoundError:

Could not find a model named "mandarin_pinyin_g2p" for g2p.