(https://github.com/ruby/irb/pull/835)
* Remove unnecessary code from the exit command's implementation
1. The parameters of `IRB.irb_exit` were never used. But there are some
libraries seem to call it with arguments + it's declared on the top-level
IRB constant. So I changed the params to anonymous splat instead of removing them.
2. `Context#exit` was completely unnecessary as `IRB.irb_exit` doesn't use
the `@irb` instance it passes. And since it's (or should be treated as)
a private method, I simply removed it.
3. The `exit` command doesn't use the status argument it receives at all.
But to avoid raising errors on usages like `exit 1`, I changed the argument to
anonymous splat instead removing it.
* Make exit an actual command
* Update readme
452b543a65
