docs: fix capitalization in doxygen comments

Change-Id: Ibf5ee5119d12d60d382b0acef8dfd08277c18fcb
diff --git a/tests/tools/nfdc/mock-nfd-mgmt-fixture.hpp b/tests/tools/nfdc/mock-nfd-mgmt-fixture.hpp
index eb197a4..ab2ec39 100644
--- a/tests/tools/nfdc/mock-nfd-mgmt-fixture.hpp
+++ b/tests/tools/nfdc/mock-nfd-mgmt-fixture.hpp
@@ -39,7 +39,7 @@
 class MockNfdMgmtFixture : public nfd::tests::MockNfdMgmtFixture
 {
 protected:
-  /** \brief respond to FaceQuery requests
+  /** \brief Respond to FaceQuery requests.
    *  \retval true the Interest matches one of the defined patterns and is responded
    *  \retval false the Interest is not responded
    */