docs: fix capitalization in doxygen comments

Change-Id: Ie61b20a3dbfc847bc14523e507102fe6fe416908
diff --git a/tests/unit/mgmt/nfd/controller-fixture.hpp b/tests/unit/mgmt/nfd/controller-fixture.hpp
index 764ff41..ae4ab3c 100644
--- a/tests/unit/mgmt/nfd/controller-fixture.hpp
+++ b/tests/unit/mgmt/nfd/controller-fixture.hpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2013-2021 Regents of the University of California.
+ * Copyright (c) 2013-2022 Regents of the University of California.
  *
  * This file is part of ndn-cxx library (NDN C++ library with eXperimental eXtensions).
  *
@@ -48,7 +48,7 @@
     m_keyChain.setDefaultIdentity(m_keyChain.createIdentity("/localhost/ControllerFixture"));
   }
 
-  /** \brief controls whether Controller's validator should accept or reject validation requests
+  /** \brief Controls whether Controller's validator should accept or reject validation requests.
    *
    *  Initially, the validator accepts all requests.
    *  Setting \p false causes validator to reject all requests.