Long, multirow format for diff(found | required)

[tribbloid]

In addition, I'd also like to change the short format for diff, which uses a Scala 3 keyword as the splitting character (|).

We should change it to a more prominent Unicode like ┃

[tribbloid]

PR should be available soon, the new diff looks like this:

newSource1.scala:15: error: type mismatch;
  Test.F[
    found   : Test.a.type (with underlying type Test.A)
    ━━━━━━━━:
    required: a.type (with underlying type a.type) where val a: Test.A
              ――(defined at newSource1.scala:13:18)
    ――(left side reduced from)
      Test.AA
  ]
      wrongf(new A)(new F[AA])
                    ^

@tek this is not the final version, we can revise it in all 1.1.0-RCx, feel free to suggest a better visualization format!

[tribbloid]

@tek submitted. Should be part of 1.1.0-RC1

[tribbloid]

released, closing