docs: simplify conf.py and fix compatibility with upcoming Sphinx 6.0

Change-Id: Iacf4a72d30babc4a7c3fab0fea619a798eff2df1
diff --git a/tools/ndn-autoconfig-server/program.cpp b/tools/ndn-autoconfig-server/program.cpp
index 542d91a..657782c 100644
--- a/tools/ndn-autoconfig-server/program.cpp
+++ b/tools/ndn-autoconfig-server/program.cpp
@@ -33,9 +33,9 @@
 
 namespace ndn::autoconfig_server {
 
-const Name HUB_DATA_NAME("/localhop/ndn-autoconf/hub");
-const Name ROUTABLE_PREFIXES_DATA_PREFIX("/localhop/nfd");
-const PartialName ROUTABLE_PREFIXES_DATA_SUFFIX("rib/routable-prefixes");
+const Name HUB_DATA_NAME{"/localhop/ndn-autoconf/hub"};
+const Name ROUTABLE_PREFIXES_DATA_PREFIX{"/localhop/nfd"};
+const PartialName ROUTABLE_PREFIXES_DATA_SUFFIX{"rib/routable-prefixes"};
 
 Program::Program(const Options& options, Face& face, KeyChain& keyChain)
   : m_face(face)
diff --git a/tools/ndn-autoconfig/multicast-discovery.cpp b/tools/ndn-autoconfig/multicast-discovery.cpp
index 550ed7f..cf87ec2 100644
--- a/tools/ndn-autoconfig/multicast-discovery.cpp
+++ b/tools/ndn-autoconfig/multicast-discovery.cpp
@@ -33,8 +33,8 @@
 
 using nfd::ControlParameters;
 
-const Name HUB_DISCOVERY_PREFIX("/localhop/ndn-autoconf/hub");
-constexpr uint64_t HUB_DISCOVERY_ROUTE_COST(1);
+const Name HUB_DISCOVERY_PREFIX{"/localhop/ndn-autoconf/hub"};
+constexpr uint64_t HUB_DISCOVERY_ROUTE_COST = 1;
 constexpr time::milliseconds HUB_DISCOVERY_ROUTE_EXPIRATION = 30_s;
 constexpr time::milliseconds HUB_DISCOVERY_INTEREST_LIFETIME = 4_s;