Add support for the `:replay` command in the REPL

[Gedochao]

The :replay command was (and is) supported by the Scala 2 REPL, while it is visibly absent in Scala 3.

scala -S 2.13
Welcome to Scala 2.13.15 (OpenJDK 64-Bit Server VM, Java 17).
Type in expressions for evaluation. Or try :help.
scala> :help
All commands can be abbreviated, e.g., :he instead of :help.
(...)
:replay [options]        reset the REPL and replay all previous commands
(...)
scala> println(1)
1

scala> :replay
replay> println(1)
1

[som-snytt]

There was a note at https://stackoverflow.com/questions/22104736/how-to-save-repl-session (since deleted) that it would be nice if :replay did an automatic :reset as demonstrated in the answer for :load, so that references to history work correctly.

I haven't checked current behavior of 2.13.