Update-MarkdownCommandHelp should have the ability to skip update of module markdown file

[sdwheeler]

Summary of the new feature / enhancement

We need to support scenarios where the module markdown file is built by commands outside of the PlatyPS module. Using the option to skip update of the module markdown file allows the author to run another tool to update the module file separately from updating the module's cmdlet files.

Proposed technical implementation details (optional)

Since New-MarkdowCommandHelp has the WithModulePage parameter I recommend using the same logic.

• Update-MarkdownCommandHelp without the parameter updates only the cmdlet files
• Update-MarkdownCommandHelp -WithModulePage updates the cmdlet files and the module markdown file

[sdwheeler]

Build https://github.com/PowerShell/platyPS/commit/27d5ffe4090f146b64c7d91453d6683c68c8ee53 added the Measure-PlatyPSMarkdown command that allows us to discover the file content type. We can use this to filter the input to other commands.