Adds support for array closures in Squiz.Functions.FunctionDeclarationArgumentSpacing

Related to #2523

Author: michalbundyra

src/Standards/Squiz/Sniffs/Functions/FunctionDeclarationArgumentSpacingSniff.php

@@ -48,6 +48,7 @@ public function register()
         return [
             T_FUNCTION,
             T_CLOSURE,
+            T_FN,
         ];
 
     }//end register()

src/Standards/Squiz/Tests/Functions/FunctionDeclarationArgumentSpacingUnitTest.inc

@@ -107,3 +107,5 @@ $a = function ($var1, $var2=false) use (
     $longVar2 ,  &$longerVar2,
     $muchLongerVar3
 ) {};
+
+fn ($a,$b = null) => $a($b);

src/Standards/Squiz/Tests/Functions/FunctionDeclarationArgumentSpacingUnitTest.inc.fixed

@@ -107,3 +107,5 @@ $a = function ($var1, $var2=false) use (
     $longVar2, &$longerVar2,
     $muchLongerVar3
 ) {};
+
+fn ($a, $b=null) => $a($b);

src/Standards/Squiz/Tests/Functions/FunctionDeclarationArgumentSpacingUnitTest.php

@@ -62,6 +62,7 @@ public function getErrorList()
             102 => 2,
             106 => 1,
             107 => 2,
+            111 => 3,
         ];
 
     }//end getErrorList()