fix: improve markdown file type detection for unstructured parser

Co-Authored-By: Aaron <AJ> Steers <[email protected]>

Author: devin-ai-integration[bot]

airbyte_cdk/sources/file_based/file_types/unstructured_parser.py

@@ -442,9 +442,9 @@ def _get_filetype(self, file: IOBase, remote_file: RemoteFile) -> Optional[FileT
             file.seek(0)
             if file_content and isinstance(file_content, bytes):
                 content_str = file_content.decode("utf-8", errors="ignore")
-                if content_str.lstrip().startswith("#"):
-                    type_based_on_content = FileType.MD
-                elif remote_file.mime_type == "text/markdown":
+                if (content_str.lstrip().startswith("#") or 
+                    remote_file.mime_type == "text/markdown" or
+                    remote_file.uri.endswith(".md")):
                     type_based_on_content = FileType.MD
                 else:
                     type_based_on_content = FileType.UNK