Avoid clangd warning about include not used directly

src/main.cpp

@@ -7,7 +7,9 @@
 #include <iostream>
 #include <string>
 
-#include "CLI/CLI.hpp"
+// Details about the IWYU pragma below can be found at
+// https://clangd.llvm.org/guides/include-cleaner#unused-include-warning
+#include "CLI/CLI.hpp" // IWYU pragma: keep
 #include "Parser.hpp"
 #include "Scanner.hpp"
 #include "Version.hpp"