Clarify mismatched width error message

[azidar]

Minor change to enable a clearer mismatched widths error message.

Contributor Checklist

• [N/A] Did you add Scaladoc to every public function/method?
• [N/A] 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?
• [N/A] Did you add appropriate documentation in docs/src?
• Did you state the API impact?
• Did you specify the code generation impact?
• Did you request a desired merge strategy?
• [N/A] Did you add text to be included in the Release Notes for this change?

Type of Improvement

• code cleanup

Desired Merge Strategy

• Squash: The PR will be squashed and merged (choose this if you have no preference.

Reviewer Checklist (only modified by reviewer)

• Did you add the appropriate labels?
• Did you mark the proper milestone (Bug fix: 3.4.x, [small] API extension: 3.5.x, API modification or big change: 3.6.0)?
• 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.