Fix typo in textsplitter docs (#825)

docs/modules/utils/combine_docs_examples/textsplitter.ipynb

@@ -152,7 +152,7 @@
    "metadata": {},
    "source": [
     "## Document creation\n",
-    "We can also use the text splitter to create \"Documents\" directly. Documents a way of bundling pieces of text with associated metadata so that chains can interact with them. We can also create documents with empty metadata though!\n",
+    "We can also use the text splitter to create \"Documents\" directly. Documents are a way of bundling pieces of text with associated metadata so that chains can interact with them. We can also create documents with empty metadata though!\n",
     "\n",
     "In the below example, we pass two pieces of text to get split up (we pass two just to show off the interface of splitting multiple pieces of text)."
    ]