chore: prefer not to use function assignment (#1381)

lua/avante/selection.lua

@@ -146,7 +146,7 @@ function Selection:create_editing_input()
     priority = PRIORITY,
   })
 
-  local submit_input = function(input)
+  local function submit_input(input)
     local full_response = ""
     local start_line = self.selection.range.start.lnum
     local finish_line = self.selection.range.finish.lnum
@@ -158,10 +158,10 @@ function Selection:create_editing_input()
     self.prompt_input:start_spinner()
 
     ---@type AvanteLLMStartCallback
-    local on_start = function(start_opts) end
+    local function on_start(start_opts) end
 
     ---@type AvanteLLMChunkCallback
-    local on_chunk = function(chunk)
+    local function on_chunk(chunk)
       full_response = full_response .. chunk
       local response_lines_ = vim.split(full_response, "\n")
       local response_lines = {}
@@ -186,7 +186,7 @@ function Selection:create_editing_input()
     end
 
     ---@type AvanteLLMStopCallback
-    local on_stop = function(stop_opts)
+    local function on_stop(stop_opts)
       if stop_opts.error then
         -- NOTE: in Ubuntu 22.04+ you will see this ignorable error from ~/.local/share/nvim/lazy/avante.nvim/lua/avante/llm.lua `on_error = function(err)`, check to avoid showing this error.
         if type(stop_opts.error) == "table" and stop_opts.error.exit == nil and stop_opts.error.stderr == "{}" then