Insights: regex capture groups failing if regex includes an `@` symbol

Created by: Joelkw

I think that @ is breaking on the backend capture groups endpoint but not in Sourcegraph. This is a valid regexp, the frontend UI tells me so (doesn’t throw a “regex formatting” error), but I get a backend error. I can search this regexp in Sourcegraph and it’s valid.

So it seems like a problem with either our backend parsing or the compute endpoint?