Nonexistent alias used not handled gracefully

[HumbleDeer]

Describe the issue

When using raptoreum-cli about, one could expect info about the raptoreum-cli RPC client (such as info about the client's version, build, etcetera). If such a command exists, Aliases could be handled more gracefully.

If it does not exist, then this missing or nonexistent command being used could be handled more gracefully.

Can you reliably reproduce the issue?

If so, please list the steps to reproduce below:

1. Run raptoreum-cli with the nonexistent alias/command about
   eg. raptoreum-cli about
2. Observe output

Expected behaviour

Running raptoreum-cli about
should return

Command "about" not found. 
See "raptoreum-cli help" for available commands

Actual behaviour

Running raptoreum-cli about
instead returns

main
error code: -32601
error message:
Method not found

Screenshots.

What version of Raptoreum Core are you using?

Raptoreum Core RPC client version v1.3.17.00-42174d8