Fix CommentHelp for when a function has other problems with it

[TylerLeonhardt]

Fixes PowerShell/vscode-powershell#2516

We weren't specifically telling PSSA to only run the one rule so other diagnostics were coming back. I would guess that this fix would also have some perf impact as well which is nice.

an example bad function that works with this change:

function CanSendGetCommentHelpRequest {
    param(
        $myParam,
        $myOtherParam,
        $yetAnotherParam
    )

    # Include other problematic code to make sure this still works
    gci
}

The test change failed before the code change and passed after the code change.

[rjmholt]

Should probably include a changelog entry