PSProvideCommentHelp should also warn on script param blocks

Summary of the new feature

As a user, I want the ## comment generation feature in the PowerShell extension for VSCode to also generate comment based help for param blocks at the top of scripts. The PowerShell extension leverages the PSProvideCommentHelp rule to do this.

Proposed technical implementation details (optional)

Invoke-ScriptAnalyzer -ScriptDefinition 'param($foo)' -Settings @{ 
  Rules = @{
      PSProvideCommentHelp = @{
          Enable = $true
          ExportedOnly = $false
          BlockComment = $true
          VSCodeSnippetCorrection = $false
          Placement = "before"
      }
  }
  }

This should yield a diagnostic record just like this does:

Invoke-ScriptAnalyzer -ScriptDefinition 'function asdf { param($foo) }' -Settings @{
  Rules = @{
      PSProvideCommentHelp = @{
          Enable = $true
          ExportedOnly = $false
          BlockComment = $true
          VSCodeSnippetCorrection = $false
          Placement = "before"
      }
  }
  }


RuleName                            Severity     ScriptName Line  Message
--------                            --------     ---------- ----  -------
PSProvideCommentHelp                Information             1     The cmdlet 'asdf' does not have a help comment.

What is the latest version of PSScriptAnalyzer at the point of writing

1.18.3

Start with the PSProvideCommentHelp rule and use Invoke-ScriptAnalyzer with the top-level param($foo) script definition as the reproduction. Compare it with the existing function param example; done means the script param block produces the same help-comment diagnostic.