PSR12/NullableTypeDeclaration: add tests with FQN true/false/null

The sniff already handles this correctly.

Author: jrfnl

src/Standards/PSR12/Tests/Functions/NullableTypeDeclarationUnitTest.inc

@@ -93,3 +93,6 @@ function fooH(): ?
 
 // Fatal error: null cannot be marked as nullable, but that's not the concern of this sniff.
 function fooI(): ? null {}
+
+// Ensure nullable FQN true/false are handled correctly.
+function fqnTrueFalseNull(? \FALSE $paramA, ? \Null $paramB) : ?   \true {}

src/Standards/PSR12/Tests/Functions/NullableTypeDeclarationUnitTest.inc.fixed

@@ -90,3 +90,6 @@ function fooH(): ?false {}
 
 // Fatal error: null cannot be marked as nullable, but that's not the concern of this sniff.
 function fooI(): ?null {}
+
+// Ensure nullable FQN true/false are handled correctly.
+function fqnTrueFalseNull(?\FALSE $paramA, ?\Null $paramB) : ?\true {}

src/Standards/PSR12/Tests/Functions/NullableTypeDeclarationUnitTest.php

@@ -49,6 +49,7 @@ protected function getErrorList()
             90 => 1,
             91 => 1,
             95 => 1,
+            98 => 3,
         ];
 
     }//end getErrorList()