Show friendly error message if symbol is not found on ClojureDocs

[katomuso]

When we use cider-clojuredocs, it shows the error message Wrong type argument: char-or-string-p, nil if a symbol we are looking for is not found. It will be nice if it will show something more meaningful instead.

[bbatsov]

I'm fine with the proposed change, just mention the bugfix in the changelog.

P.S. I'll be cutting a new release of CIDER soon, so this would be a good time to also add some documentation about cider-cheatsheet with a few screenshots, etc.

[katomuso]

P.S. I'll be cutting a new release of CIDER soon, so this would be a good time to also add some documentation about cider-cheatsheet with a few screenshots, etc.

I was planning to add customizable variables for the cheatsheet tomorrow, and then update the documentation the day after tomorrow. Will this be in time for the new release?

[bbatsov]

Take your time, there's no rush. It will be late for this release, at it happened just now, but there's no problem to include those changes in the next one.