neovim: fix lsp error display using diagflow and some deprecated api stuff

.config/nvim/lua/klowner/plugins/lsp/lspconfig.lua

@@ -74,13 +74,22 @@ return {
 
     -- Change the Diagnostic symbols in the sign column (gutter)
     -- (not in youtube nvim video)
-    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
+    vim.diagnostic.config({
+      virtual_text = false, -- diagflow handles display
+      float = {
+        style = 'minimal',
+      },
+      signs = {
+        text = {
+          [vim.diagnostic.severity.ERROR] = ' ',
+          [vim.diagnostic.severity.WARN] = ' ',
+          [vim.diagnostic.severity.HINT] = '󰠠 ',
+          [vim.diagnostic.severity.INFO] = ' ',
+        },
+      },
+    })
 
-    mason_lspconfig.setup_handlers({
+    mason_lspconfig.setup({
       -- default handler for installed servers
       function(server_name)
         lspconfig[server_name].setup({