Turn on StyLua's collapse_simple_statement

[oriori1703]

Turn on StyLua's collapse_simple_statement for functions.

This could lead a major improvement for code that's heavy on anonymous function, like defining a lot of keymaps in succession.
for example:

diff --git a/lua/kickstart/plugins/debug.lua b/lua/kickstart/plugins/debug.lua
index 753cb0c..2311c4f 100644
--- a/lua/kickstart/plugins/debug.lua
+++ b/lua/kickstart/plugins/debug.lua
@@ -26,56 +26,14 @@ return {
   },
   keys = {
     -- Basic debugging keymaps, feel free to change to your liking!
-    {
-      '<F5>',
-      function()
-        require('dap').continue()
-      end,
-      desc = 'Debug: Start/Continue',
-    },
-    {
-      '<F1>',
-      function()
-        require('dap').step_into()
-      end,
-      desc = 'Debug: Step Into',
-    },
-    {
-      '<F2>',
-      function()
-        require('dap').step_over()
-      end,
-      desc = 'Debug: Step Over',
-    },
-    {
-      '<F3>',
-      function()
-        require('dap').step_out()
-      end,
-      desc = 'Debug: Step Out',
-    },
-    {
-      '<leader>b',
-      function()
-        require('dap').toggle_breakpoint()
-      end,
-      desc = 'Debug: Toggle Breakpoint',
-    },
-    {
-      '<leader>B',
-      function()
-        require('dap').set_breakpoint(vim.fn.input 'Breakpoint condition: ')
-      end,
-      desc = 'Debug: Set Breakpoint',
-    },
+    { '<F5>', function() require('dap').continue() end, desc = 'Debug: Start/Continue' },
+    { '<F1>', function() require('dap').step_into() end, desc = 'Debug: Step Into' },
+    { '<F2>', function() require('dap').step_over() end, desc = 'Debug: Step Over' },
+    { '<F3>', function() require('dap').step_out() end, desc = 'Debug: Step Out' },
+    { '<leader>b', function() require('dap').toggle_breakpoint() end, desc = 'Debug: Toggle Breakpoint' },
+    { '<leader>B', function() require('dap').set_breakpoint(vim.fn.input 'Breakpoint condition: ') end, desc = 'Debug: Set Breakpoint' },
     -- Toggle to see last session result. Without this, you can't see session output in case of unhandled exception.
-    {
-      '<F7>',
-      function()
-        require('dapui').toggle()
-      end,
-      desc = 'Debug: See last session result.',
-    },
+    { '<F7>', function() require('dapui').toggle() end, desc = 'Debug: See last session result.' },
   },
   config = function()
     local dap = require 'dap'

This was originally part of #1481