Enhance PSUseConsistentWhiteSpace to exclude more special cases when using unary operators

Found when discussing PR #949 , which already tweaked PSUseConsistentWhiteSpace when using unary operators inside parenthesis.
This adds another special case where the rule should be excluded. The community is welcome to provide more cases that need to be treated specially.

Steps to reproduce

Invoke-Formatter -ScriptDefinition '$r = $a -lt -$var'                                                                                                       

Expected behavior

$r = $a -lt -$var

Actual behavior

$r = $a -lt - $var

Environment data

This applies also to the latest version of the development branch.

> $PSVersionTable
Name                           Value
----                           -----
PSVersion                      5.1.16299.251
PSEdition                      Desktop
PSCompatibleVersions           {1.0, 2.0, 3.0, 4.0...}
BuildVersion                   10.0.16299.251
CLRVersion                     4.0.30319.42000
WSManStackVersion              3.0
PSRemotingProtocolVersion      2.3
SerializationVersion           1.1.0.1

> (Get-Module -ListAvailable PSScriptAnalyzer).Version | ForEach-Object { $_.ToString() }
1.16.1

Riproduci il problema con Invoke-Formatter e la regola PSUseConsistentWhiteSpace utilizzando la definizione dello script mostrata. Traccia il comportamento del formatter per l’espressione con l’operatore unario e verifica che la modifica completata mantenga $r = $a -lt -$var senza inserire uno spazio tra il meno unario e $var.