The need for this became obvious (at least to me) while working to elevate our embedded shortcode documentation to its own section. They re-branded a while ago, and while the public's transition has been slow, the new brand has been stable for quite a while.

• Twitter => "X"
• tweet => "post" or "X post"

This change touches a few things, including:

• Internal shortcode aliasing (maybe)
• Replacement and deprecation of privacy config
• Replacement and deprecation of services config
• Renaming (or making copies of) the internal templates (twitter and twitter_simple)
• Updating tests

We'll leave the twitter_cards template alone because, at least for now, the term "Twitter Cards" seems to still be the recognized phrase.

Keep in mind that site and theme authors may have created their own tweet, twitter, or twitter_simple shortcodes, so calling shortcodes by these names should not trigger a warning. We need to handle this on the receiving end (i.e., after we've determined that we're using an embedded shortcode).

I've got a working branch, but will refrain from submitting unless this proposal is approved.