Improve :expr input format

[sheluchin]

When using nrepl-client from a babashka task, the current approach requires that for the :expr, you either pass a string literal like "(+ 1 1)" or an expression producing a string, like (str '(+ 1 1)). The latter option has the benefit of letting your editor provide syntax highlighting and code navigation, but it's still a little awkward and quoted forms don't get linted as well.

Please consider improving the ergonomics around this use case for future iterations 🙏