0.1.157

DocChatAgentConfig: new param
add_fields_to_content.

This lets you add additional fields into the "main" content field of a document. E.g. if a movie-related Document has fields year,
genre, rating, these can be added to the main content field,
as key=value pairs, e.g. year=1989, genre=Crime. (The original fields are left intact, so can still be used for filtering).
Adding fields to the content can help with retrieval since these would be taken into account when creating embeddings,
as well as during keyword/lexical search.
See test test_doc_chat_add_content_fields here: https://github.com/langroid/langroid/blob/main/tests/main/test_doc_chat_agent.py