[cleanup] improve comment alignment in gtlist.h

[credo-quia-absurdum]

This change improves the readability of comments in gtlist.h.

Previously, the comment columns were visually aligned by placing commas in the
same positions as the actual argument separators. While this kept the columns
technically aligned, the presence of "floating commas" in the comments made the
structure harder to parse at a glance.

The updated version replaces those comma placeholders with clearer alignment
cues, making the layout easier to understand.

No behavioral changes.

Part of #84834, cc @dotnet/samsung
@SkyShield @namu-lee

[Copilot]

Pull Request Overview

This PR improves the visual alignment of comments in gtlist.h by replacing comma-based placeholders with a clearer column alignment scheme using pipe characters (|) and arrows (v). The new format makes the comment structure more readable by explicitly showing the vertical alignment between the column headers and the actual GTNODE macro parameters.

Key Changes:

• Replaced floating commas in comments with explicit pipe characters (|) to show column boundaries
• Added arrows (v) to clearly indicate which comment header corresponds to which macro parameter
• Improved visual clarity while maintaining the same informational content

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[tannergooding]

I do not personally find this to be more readable, rather I find it visually distracting instead

I think it would be less problematic if this were just repeating the commas down or instead made each column bigger so all "column headers" could be on one line

but I also think this is fine as it is and can probably avoid unnecessary churn

[credo-quia-absurdum]

Thanks for your review and suggestions. I've updated the formatting by repeating the commas down from the existing comma, as you recommended.

If you still feel this change introduces unnecessary churn, please feel free to close the PR. For context, as a newcomer to .NET, the original formatting was a bit hard for me to grasp at first glance, so I tried adjusting it for readability.