Bring back doc for `Get-Counter` cmdlet for PS7

[SteveL-MSFT]

Documentation Issue

Get-Counter is coming back for PS7 (note that Import-Counter and Export-Counter are NOT): PowerShell/PowerShell#10933

Context of the issue

• URL to the article (Docs or GitHub URL):

• Issue affects the following content (check all that apply):

  Cmdlet reference & about_ topics

  • Version 7 content
  • Version 6 content
  • Version 5.1 content

  Conceptual articles

  • Fundamental conceptual articles
  • Script sample articles
  • DSC articles
  • Gallery articles
  • JEA articles
  • WMF articles
  • SDK articles

• Is the issue specific to a platform (Y/N - Win/macOS/Linux): Win

Detailed description of the issue

[iSazonov]

@SteveL-MSFT @sdwheeler The Get-Counter code was cleaned up for compliance. Should we update the documentation too?

[sdwheeler]

@iSazonov If the compliance changes affected the function, then we need to document it. What were the changes?

[iSazonov]

@sdwheeler I think @SteveL-MSFT or @TravisEz13 could add more information.