[Feature Request] Check if config already exists before creating it

[Rizhiy]

Currently, on init the config file is always written even if it already exists, potentially overriding saved user config.

Please add a file exists check before:

scratch.nvim/lua/scratch/config.lua

Line 166 in 9b35cf9

file:write(vim.fn.json_encode(default_config))

[Rizhiy]

No longer relevant, since now you can just pass in config.