docs: Documentation corrections

Installation instructions incorrectly suggested to install ndn-cxx
package from Ubuntu PPA archive.  Instead, ndn-cxx-dev package should be
installed.

Change-Id: I68a645011f31ba7b3a63fda0fb2811006a83e8ef
diff --git a/docs/Doxyfile b/docs/Doxyfile
index 878da69..c69fcb2 100644
--- a/docs/Doxyfile
+++ b/docs/Doxyfile
@@ -1965,7 +1965,9 @@
                          PROTECTED_WITH_TESTS_ELSE_PRIVATE=private \
                          VIRTUAL_WITH_TESTS \
                          DECL_OVERRIDE \
-                         ATTRIBUTE_HELPER_CPP
+                         ATTRIBUTE_HELPER_CPP \
+                         NDN_CXX_KEYCHAIN_REGISTER_PIB \
+                         NDN_CXX_KEYCHAIN_REGISTER_TPM
 
 
 # If the MACRO_EXPANSION and EXPAND_ONLY_PREDEF tags are set to YES then this