Add from_generator to package reference

Author: mariosasko

docs/source/package_reference/main_classes.mdx

@@ -16,6 +16,7 @@ The base class [`Dataset`] implements a Dataset backed by an Apache Arrow table.
     - from_buffer
     - from_pandas
     - from_dict
+    - from_generator
     - data
     - cache_files
     - num_columns

src/datasets/arrow_dataset.py

@@ -950,7 +950,7 @@ def from_generator(
         """Create a Dataset from a generator.
 
         Args:
-            generator (:obj:`Callable`): A callable object that returns an object that supports the `iter()` protocol.
+            generator (:obj:`Callable`): A callable object that returns an object that supports the `iter` protocol.
             features (:class:`Features`, optional): Dataset features.
             cache_dir (:obj:`str`, optional, default ``"~/.cache/huggingface/datasets"``): Directory to cache data.
             keep_in_memory (:obj:`bool`, default ``False``): Whether to copy the data in-memory.