add more vars to text splitter (#5503)

langchain/text_splitter.py

@@ -443,6 +443,8 @@ class RecursiveCharacterTextSplitter(TextSplitter):
                 "\nfunction ",
                 "\nconst ",
                 "\nlet ",
+                "\nvar ",
+                "\nclass ",
                 # Split along control flow statements
                 "\nif ",
                 "\nfor ",