print tab indentation in REPL

[som-snytt]

Reproduction steps

scala 2.13.7> 42
val res0: Int = 42

scala 2.13.7> 42 // print
                  42 // : Int(42)

Problem

scala 2.13.6> 42
val res0: Int = 42

scala 2.13.6> 42 // print
42 // : Int(42)
scala 2.13.6> 42 // print

Nicest of all would be for it to line up with the REPL input text.

Noticed on the forum

[SethTisue]

effort might better be spent on a different design, maybe a :print command? magic tab completions aren't discoverable and are especially undiscoverable since we only have exactly one of them

note that the Scala 3 REPL doesn't have the feature at all, at present anyway

[som-snytt]

Alternatively, reprint the current line with comment replaced with desired output!

Also alternatively, have fancy arrow graphics for this and for multi-errors on multi-line input!

This issue is really about nailing down REPL output.