Improve handling of deprecated methods/classes in the REPL

[scabug]

= problem =
When using the REPL, deprecated methods/classes can only be noticed after using them.

warning: there were 1 deprecation warnings; re-run with -deprecation for details

= analysis =
It would be better if deprecated methods would be recognizable in tab-completion and in usage/while typing.

= enhancement recommendation =
Options to display deprecated methods/classes more clearly could be:

• A "strike-through effect"
• Some coloring (related to SI-4223)
• Some marking like appending "(d)" in the tab completion

If that would work, it might be possible to consider dropping the "warning after usage" when running scala without "-deprecation"

[scabug]

Imported From: https://issues.scala-lang.org/browse/SI-4229?orig=1
Reporter: @soc
Attachments:

• scala-completion.png (created on Feb 9, 2011 10:39:41 AM UTC, 19537 bytes)
• scala-completion-strikethrough.png (created on Feb 9, 2011 10:40:01 AM UTC, 19137 bytes)

[scabug]

@soc said:
Now

[scabug]

@soc said:
Proposal (Option 1)

[SethTisue]

as of Scala 2.13.3, deprecated methods have a "(deprecated)" after them in tab completion:

[SethTisue]

Ideally, deprecated methods would be presented last, in their own group. That may yet happen under #12272