[Feature] Add "alias" for "pwsh", short for "powershell"

[o-l-a-v]

Is your feature request related to a problem? Please describe.

Some other code in markdown highlighters, like GitHub itself, support defining pwsh as well as powershell for PowerShell.

Current behavior:

Would be nice if this Obsidian extension could add support for this too.

I don't know if it can be added to this extension, or if it should be raised upstream with either Shiki or Obsidian.

Describe the solution you'd like

This:

```pwsh
Write-Output -InputObject 'Hello'
```

Should be highlighted as PowerShell too.

Additional context
Add any other context or screenshots about the feature request here.