[Feature] Make common_on_attach configurable (#1024)

utils/installer/lv-config.example.lua

@@ -50,6 +50,17 @@ O.treesitter.ensure_installed = "maintained"
 O.treesitter.ignore_install = { "haskell" }
 O.treesitter.highlight.enabled = true
 
+-- generic LSP settings
+-- you can set a custom on_attach function that will be used for all the language servers
+-- See <https://github.com/neovim/nvim-lspconfig#keybindings-and-completion>
+-- O.lsp.on_attach_callback = function(client, bufnr)
+--   local function buf_set_option(...)
+--     vim.api.nvim_buf_set_option(bufnr, ...)
+--   end
+--   --Enable completion triggered by <c-x><c-o>
+--   buf_set_option("omnifunc", "v:lua.vim.lsp.omnifunc")
+-- end
+
 -- python
 O.lang.python.diagnostics.virtual_text = true
 O.lang.python.analysis.use_library_code_types = true