Rename all object interface traits, $ => Obj

[jackkoenig]

Fixes #5212 (well works around IntelliJ's bug but what are you gonna do 🤷‍♀️)

Contributor Checklist

• Did you add Scaladoc to every public function/method?
• Did you add at least one test demonstrating the PR?
• Did you delete any extraneous printlns/debugging code?
• Did you specify the type of improvement?
• Did you add appropriate documentation in docs/src?
• Did you request a desired merge strategy?
• Did you add text to be included in the Release Notes for this change?

Type of Improvement

• Bugfix

Desired Merge Strategy

• Squash

Release Notes

This works around a bug in IntelliJ which assumes that $ signifies an inner class and thus it does not properly find public APIs defined in these traits.

Reviewer Checklist (only modified by reviewer)

• Did you add the appropriate labels? (Select the most appropriate one based on the "Type of Improvement")
• Did you mark the proper milestone (Bug fix: 3.6.x, 5.x, or 6.x depending on impact, API modification or big change: 7.0)?
• Did you review?
• Did you check whether all relevant Contributor checkboxes have been checked?
• Did you do one of the following when ready to merge:
  • Squash: You/ the contributor Enable auto-merge (squash) and clean up the commit message.
  • Merge: Ensure that contributor has cleaned up their commit history, then merge with Create a merge commit.

[jackkoenig]

These two are not acceptable to waive, it was a bit annoying to show this but what I did was:

//> using repository https://central.sonatype.com/repository/maven-snapshots
//> using scala 2.13.18
//> using dep org.chipsalliance::chisel:7.10.0
//> using plugin org.chipsalliance:::chisel-plugin:7.10.0
//> using options -unchecked -deprecation -language:reflectiveCalls -feature -Xcheckinit
//> using options -Xfatal-warnings -Ywarn-dead-code -Ywarn-unused -Ymacro-annotations

import chisel3._
import chisel3.util._
// _root_ disambiguates from package chisel3.util.circt if user imports chisel3.util._
import _root_.circt.stage.ChiselStage

class Foo extends Module {
  val out = IO(Output(Bool()))

  out := 0x0f.U === BitPat("b??0011??")
}

object Main extends App {
  println(
    ChiselStage.emitSystemVerilog(
      gen = new Foo,
      firtoolOpts = Array("-disable-all-randomization", "-strip-debug-info", "-default-layer-specialization=enable")
    )
  )
}

Then I get the classpath of this from scala-cli

scala-cli compile . --print-class-path

Then I took that classpath and replaced the chisel jar with a locally published one with this change, then I manually ran that with java which resulted in a runtime error.

[seldridge]

Nice. This is a clever way of solving this.

<rant>

We should not be making code changes based on bugs in editors. Jetbrains has repeatedly shown that they either are incapable of properly supporting Scala, they don't care about supporting Scala, or they are just grossly incompetent developers that don't know what they are doing. This is not the first bug (nor I suspect the last bug) in their $800/seat/year editor.

The right thing here is to open a bug report on IntelliJ IDEA and get them to fix their "Leading IDE for Professional Development": https://youtrack.jetbrains.com/issues/IDEA

I have never seen this problem with any other editor, lsp, etc.

</rant>