Recognize eventID in circular search and link to synonym slug

[jracusin]

Description

Once synonym groups are enabled and backfilled (#2662, #2750, #2620), add logic in Circulars search bar such that when an eventID (with REGEX e.g. "GRB 123456A" and "GRB123456A") recognize it as an eventID, and link to appropriate synonym group slug.

Acceptance criteria

• recognize syntax for an eventID
• add REGEX to deal with variations on recognizing an eventID
• link to synonym group rather than perform a text search
• have some way to do a text search in case that's relevant, maybe using quotes, that doesn't link to the synonym group
• make the REGEX a variable that we can link to in documentation