PR Summary

When CheckParameter is $true for the rule PSUseConsistentWhitespace, it checks whitespace between parameters by inspecting the AST. It gets all direct children of each CommandAst and checks, in order, that each's extent is separated by exactly 1 character.

This relies on the implicit assumption that the AST returns the children in something resembling token order.

In the case of redirect operators, this is not always the case (they anecdotally appear to be returned in the order of the stream they're redirecting). See the issue here for more detailed breakdown.

This PR adds sorting of the children before subsequently performing the same checks on the tokens extents.

Running the below across PS5.1 and PS7.4 with and without the PR change applied shows the performance impact of the change to be minimal.

Measure-Command {
    foreach ($i in 1..10000) {
        Invoke-Formatter -ScriptDefinition "Invoke-Foo $i 3>&1 2>&1 1>`$null" -Settings @{
            Rules = @{
                PSUseConsistentWhitespace = @{
                    Enable         = $true
                    CheckParameter = $true
                }
            }
        }
    }
}

The 'speedup' is presumably that we're no longer emitting a diagnostic record

Fixes #2000

PR Checklist

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  • Use the present tense and imperative mood when describing your changes
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• Change is not breaking
• Make sure all .cs, .ps1 and .psm1 files have the correct copyright header
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