Preemption for one-shot disabling embed functionality (stop link metadata)

Essentially, it would be useful if, for some links, one could "preempt" the "embedder" in a way that it doesn't reach out and grab the link metadata.

• ! https://example.com
• .https://example.com
• -https://example.com

Something like that.

It might also be useful to disable this By default for a pasted set of links the current functionality if you paste a set of URLs is that the embedder fetches metadata for each URL sent to the channel. For large sets of URLs that may be informational to the channel, this can be annoying since it might return metadata for 10 or so links at a time and flood the channel. This is not the main focus of this ticket though, just an addendum. Perhaps to include this, one could do something like:

!!!
https://example1.com
https://www.google.com
https://www.yoursitehere.com
!!!

Referencing bug #3467 , it also seems that simply turning on code blocks doesn't really help, either.

Thanks for the great work you guys rock(et)!

Start by reviewing the behavior described here and the related bug #3467, then locate the link-metadata embedder entry point. Decide and document how a one-shot marker should suppress metadata fetching and how grouped pasted URLs should behave. Done means the chosen syntax reliably prevents unwanted previews without changing ordinary link embedding.