Honor [Parameter(DontShow)] in New-MarkdownCommandHelp output

[Copilot]

Microsoft.PowerShell.PlatyPS 1.0.1 was emitting hidden parameters in generated markdown even when parameters were annotated with [Parameter(DontShow)]. This change aligns New-MarkdownCommandHelp behavior with expected PowerShell metadata semantics by excluding hidden parameters from generated help.

• What changed

  • NewMarkdownHelpCommand now sets TransformSettings.ExcludeDontShow = true when generating command help.
  • TransformBase now enforces ExcludeDontShow consistently in:
    • parameter collection (GetParameters)
    • syntax generation (GetSyntaxItem, both positional and named parameter passes)

• Regression coverage

  • Added a focused Pester scenario in NewMarkdownHelp.Tests.ps1 that defines a function with:
    • one public parameter
    • two [Parameter(DontShow)] parameters
  • Asserts hidden parameters are absent from:
    • markdown parameter sections
    • imported command model parameter/syntax content

• Example scenario covered

  function Test-DontShowParameter {
      [CmdletBinding()]
      param(
          [string]$Public,
          [Parameter(DontShow)][string]$Hidden,
          [Parameter(DontShow)][string]$Break
      )
  }
  
  New-MarkdownCommandHelp -Command (Get-Command Test-DontShowParameter) -OutputFolder $TestDrive
  # Expected: only -Public appears in generated help content

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This change is