Improve function search by imagining its docstring, parameter and return value

[doomspec]

https://github.com/EvoEvolver/EvoNote/blob/d2471e8b21a9dca6043bd3ab83d7108a2f2288da/evonote/search/code_searcher.py#L33

I have written the plan in the function. We just need more prompt engineering to finish it.