idea/feature request: Show that a command is currently executing in the REPL

[rutchkiwi]

Hello.

For example, when running my test suite in the REPL (or any other long running command) it'd be nice to see that something is executing in the REPL. For example with a spinner.
This would also make it easy to spot when something is stuck.

[cmf]

Yes, this would definitely be a great idea.