Remove SourceLineNoCol

[jackkoenig]

It causes issues in downstream codebases and really adding it just isn't worth the pain.

Removes an API added in #3414

Will need to be included in #3430 and #3431.

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?

No release notes

Type of Improvement

• API modification
• BugFix

(Modification of an API that is not-yet-released)

Desired Merge Strategy

• Squash

Release Notes

Tweak emission of source locators in error messages to match format in emitting FIRRTL (removed the : between filename and line number).

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: 3.5.x, 3.6.x, or 5.x depending on impact, API modification or big change: 6.0)?
• 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), clean up the commit message, and label with Please Merge.
  • Merge: Ensure that contributor has cleaned up their commit history, then merge with Create a merge commit.