refactor(coding): replace treesj with mini.splitjoin for code splitting/joining

lua/plugins/coding.lua

@@ -44,14 +44,4 @@ return {
             })
         end,
     },
-
-    -- split join code
-    {
-        'Wansmer/treesj',
-        keys = { '<space>m', '<space>j', '<space>s' },
-        dependencies = { 'nvim-treesitter/nvim-treesitter' }, -- if you install parsers with `nvim-treesitter`
-        config = function()
-            require('treesj').setup()
-        end,
-    },
 }