Error generating About: StartIndex cannot be less than zero

[rrg92]

Prerequisites

• [X] Write a descriptive title.
• [X] Make sure you are able to repro it on the latest released version
• [X] Search the existing issues.

Steps to reproduce

1. Create a markdown file, (e.g., 'C:\temp\PlatyTemp\about_PlatyProblem.md') with that content:

# Platy Problem
## about_PlatyProblem

# SHORT DESCRIPTION 

Demonstrates a problem with PlatyPS when a long word is present.

# LONG DESCRIPTION 

プロバイダーもコマンドをエクスポートします。これらのコマンド名は、一般的にプロバイダー名で始まる場合が多いです。エクスポートされたコマンドのパターンについては、プロバイダーのドキュメントを参照してください。

2. Run New-ExternalHelp -Path C:\temp\PlatyTemp -OutputPath C:\temp\PlatyTemp -Force

Expected behavior

Under normal circumstances, PlatyPS should wrap text lines based on the `MaxAboutWidth` setting (default 80), ensuring that once a line exceeds the maximum X characters, the remaining text is moved to the next line.

Actual behavior

An exception occurs with the following message:  
`StartIndex cannot be less than zero`

Error details

at System.String.Substring(Int32 startIndex, Int32 length)
   at Markdown.MAML.Renderer.TextRenderer.WrapAndAppendLines(String text, StringBuilder sb)
   at Markdown.MAML.Renderer.TextRenderer.AddAboutParagraph(ParagraphNode paragraphNode)
   at Markdown.MAML.Renderer.TextRenderer.AboutMarkdownToString(DocumentNode document)

Environment data

ModuleType Version    Name                                ExportedCommands
---------- -------    ----                                ----------------
Script     0.14.2     platyPS                             {New-MarkdownHelp, Get-MarkdownMetadata, New-ExternalHelp, New-YamlHelp...}



Name                           Value
----                           -----
PSVersion                      5.1.19041.4894
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.19041.4894
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

Visuals

No response