Remove the HelpUri parameter from New-MarkdownModuleFile & Update-MarkdownModuleFile

[sdwheeler]

Summary of the new feature / enhancement

The -HelpUri parameter is used to set the value of the HelpUri for a CommandHelp object. It doesn't apply to a Module. Modules use the -HelpInfoUri parameter.

These cmdlets in PlatyPS build https://github.com/PowerShell/platyPS/commit/27d5ffe4090f146b64c7d91453d6683c68c8ee53 have this parameter.

Proposed technical implementation details (optional)

No response