Better print file-api exceptions

Signed-off-by: Cristian Le <git@lecris.dev>

Author: LecrisUT

src/scikit_build_core/cmake.py

@@ -266,7 +266,7 @@ def configure(
                 self.file_api = load_reply_dir(self._file_api_query)
         except ExceptionGroup as exc:
             logger.warning("Could not parse CMake file-api")
-            logger.debug(str(exc))
+            logger.debug(str(exc.exceptions))
 
     def _compute_build_args(
         self,