feat(api): enable customizable calls functions (#457)

Signed-off-by: Aaron Pham <contact@aarnphm.xyz>

lua/avante/types.lua

@@ -12,10 +12,61 @@
 ---@class vim.api.keyset.create_autocmd.opts: vim.api.keyset.create_autocmd
 ---@field callback? fun(ev:vim.api.create_autocmd.callback.args):boolean?
 
---- @param event string | string[] (string|array) Event(s) that will trigger the handler
---- @param opts vim.api.keyset.create_autocmd.opts
---- @return integer
+---@param event string | string[] (string|array) Event(s) that will trigger the handler
+---@param opts vim.api.keyset.create_autocmd.opts
+---@return integer
 function vim.api.nvim_create_autocmd(event, opts) end
 
+---@class vim.api.keyset.user_command.callback_opts
+---@field name string
+---@field args string
+---@field fargs string[]
+---@field nargs? integer | string
+---@field bang? boolean
+---@field line1? integer
+---@field line2? integer
+---@field range? integer
+---@field count? integer
+---@field reg? string
+---@field mods? string
+---@field smods? UserCommandSmods
+
+---@class UserCommandSmods
+---@field browse boolean
+---@field confirm boolean
+---@field emsg_silent boolean
+---@field hide boolean
+---@field horizontal boolean
+---@field keepalt boolean
+---@field keepjumps boolean
+---@field keepmarks boolean
+---@field keeppatterns boolean
+---@field lockmarks boolean
+---@field noautocmd boolean
+---@field noswapfile boolean
+---@field sandbox boolean
+---@field silent boolean
+---@field split string
+---@field tab integer
+---@field unsilent boolean
+---@field verbose integer
+---@field vertical boolean
+
+---@class vim.api.keyset.user_command.opts: vim.api.keyset.user_command
+---@field nargs? integer | string
+---@field range? integer
+---@field bang? boolean
+---@field desc? string
+---@field force? boolean
+---@field complete? fun(prefix: string, line: string, pos?: integer): string[]
+---@field preview? fun(opts: vim.api.keyset.user_command.callback_opts, ns: integer, buf: integer): nil
+
+---@alias vim.api.keyset.user_command.callback fun(opts?: vim.api.keyset.user_command.callback_opts):nil
+
+---@param name string
+---@param command vim.api.keyset.user_command.callback
+---@param opts? vim.api.keyset.user_command.opts
+function vim.api.nvim_create_user_command(name, command, opts) end
+
 ---@type boolean
 vim.g.avante_login = vim.g.avante_login