feat(diag): add lsp diagnostic config

lua/config/plugins/lsp_diagnostic.lua

@@ -0,0 +1,5 @@
+local signs = { Error = " ", Warn = " ", Hint = "󱩎 ", Info = " " }
+for type, icon in pairs(signs) do
+  local hl = "DiagnosticSign" .. type
+  vim.fn.sign_define(hl, { text = icon, texthl = hl, numhl = "" })
+end