Fix double '\' when handling classes in the global namespace (#1329)

src/Analysers/ReflectionAnalyser.php

@@ -108,7 +108,7 @@ protected function analyzeFqdn(string $fqdn, Analysis $analysis, array $details)
             'context' => $context,
         ];
         $normaliseClass = function (string $name): string {
-            return '\\' . $name;
+            return '\\' . ltrim($name, '\\');
         };
         if ($parentClass = $rc->getParentClass()) {
             $definition['extends'] = $normaliseClass($parentClass->getName());