fix: don't use binary mode

hooks/gen_docs/utils.py

@@ -23,15 +23,15 @@ def copy_file(
         NOTE: The default header will only contain correct information if the caller of
         this function is the one which should be referenced in the header
     """
-    with dest.open("w+b") as file_dest, source.open("rb") as file_source:
+    with dest.open("w+") as file_dest, source.open("r") as file_source:
         if not add_header:
             shutil.copyfileobj(file_source, file_dest)
             return
         if header is None:
-            header_encoded = f"<!-- This file is autogenerated by {Path(inspect.stack()[1].filename).relative_to(ROOT)}. -->\n\n".encode()
+            header_encoded = f"<!-- This file is autogenerated by {Path(inspect.stack()[1].filename).relative_to(ROOT)}. -->\n\n"
         else:
-            header_encoded = header.encode()
-        with TemporaryFile() as file_header:
+            header_encoded = header
+        with TemporaryFile(mode="w+") as file_header:
             file_header.write(header_encoded)
             file_header.seek(0)
             shutil.copyfileobj(file_header, file_dest)