Add scoper for incorrectly-namespaced constant

scoper.inc.php

@@ -92,6 +92,17 @@ return [
                 );
             }
 
+            return $contents;
+        },
+        function ($filePath, $prefix, $contents) {
+            if ($filePath === realpath(__DIR__ . '/src/psalm.php')) {
+                return str_replace(
+                    '\\' . $prefix . '\\PSALM_VERSION',
+                    'PSALM_VERSION',
+                    $contents
+                );
+            }
+
             return $contents;
         },
     ],