fix: add missing slash on startup for certain log_dir paths (#1500)

Author: kostasrim

src/server/dfly_main.cc

@@ -622,7 +622,8 @@ void sigill_hdlr(int signo) {
 void PrintBasicUsageInfo() {
   std::cout << "* Logs will be written to the first available of the following paths:\n";
   for (const auto& dir : google::GetLoggingDirectories()) {
-    std::cout << dir << "dragonfly.*\n";
+    const string_view maybe_slash = absl::EndsWith(dir, "/") ? "" : "/";
+    std::cout << dir << maybe_slash << "dragonfly.*\n";
   }
   std::cout << "* For the available flags type dragonfly [--help | --helpfull]\n";
   std::cout << "* Documentation can be found at: https://www.dragonflydb.io/docs";