fix: type of temperature and top_p

feat!: replace history_size option with max_characters and max_messages

fix: bug that included loading indicator as history

feat: add option for temperature and top_p

feat: make default system prompt a bit shorter

feat: set modeline in buffer and add g:askgpt_file_name option

fix: error that happens when reopen the same buffer

fix: suppress error when foldmethod is set not manual (#1)

fix: improve error handling when curl command failed

fix: bug that :AskGPT with range always made a new buffer

fix: marker handling in block quote

fix: make sure that prompt is always present

fix: make sure that ignore askgpt in prompt

feat: change filetype to askgpt.markdown

fix: bug that makes incorrect fold when open new buffer