Streamline navigating from `*cider-error*` to the inspector

[vemv]

Context

*cider-error* shows ex-data when displaying a given exception. Said ex-data can be intrincate, and therefore jumping to the Inspector is a natural thing to want.

Currently, if I press RET, nothing will happen (other than newline: Buffer is read-only: #<buffer *cider-error*>)

Proposal

When hitting RET, the given exception should be inspected.

Notes

*cider-error* can have N causes. RET ing each cause should inspect a different object.

It probably would be idea to store in a var (e.g. cider.nrepl.middleware.ex/xxx) the current exception being shown in *cider-error*, given that it doesn't necessarily corresponds to *e.

[rrudakov]

Maybe instead of RET it could be p (the same way it's done in debugger)? Hitting RET on a stacktrace item jumps to the location, I guess it might be confusing.

[vemv]

Both considerations sound right to me 👍 - thanks

[vemv]

Besides from p I'm making this simply clickable - good gateway drug to bring more users to the Inspector