Document loader/debug (#7750)

Description: Added debugging output in DirectoryLoader to identify the
file being processed.
Issue: [Need a trace or debug feature in Lanchain DirectoryLoader
#7725](https://github.com/hwchase17/langchain/issues/7725)
Dependencies: No additional dependencies are required.
Tag maintainer: @rlancemartin, @eyurtsev
This PR enhances the DirectoryLoader with debugging output to help
diagnose issues when loading documents. This new feature does not add
any dependencies and has been tested on a local machine.

langchain/document_loaders/directory.py

@@ -79,15 +79,17 @@ class DirectoryLoader(BaseLoader):
             path: Directory path.
             docs: List of documents to append to.
             pbar: Progress bar. Defaults to None.
+
         """
         if item.is_file():
             if _is_visible(item.relative_to(path)) or self.load_hidden:
                 try:
+                    logger.debug(f"Processing file: {str(item)}")
                     sub_docs = self.loader_cls(str(item), **self.loader_kwargs).load()
                     docs.extend(sub_docs)
                 except Exception as e:
                     if self.silent_errors:
-                        logger.warning(e)
+                        logger.warning(f"Error loading file {str(item)}: {e}")
                     else:
                         raise e
                 finally:
@@ -134,6 +136,3 @@ class DirectoryLoader(BaseLoader):
             pbar.close()
 
         return docs
-
-
-#