feat(diagnostic): add diagnostic config (nvim-lua#1335)

Co-authored-by: gelocraft <gelocraft@users.noreply.github.com>

Author: gelocraft

init.lua

@@ -735,15 +735,34 @@ require('lazy').setup({
         end,
       })
 
-      -- Change diagnostic symbols in the sign column (gutter)
-      -- if vim.g.have_nerd_font then
-      --   local signs = { ERROR = '', WARN = '', INFO = '', HINT = '' }
-      --   local diagnostic_signs = {}
-      --   for type, icon in pairs(signs) do
-      --     diagnostic_signs[vim.diagnostic.severity[type]] = icon
-      --   end
-      --   vim.diagnostic.config { signs = { text = diagnostic_signs } }
-      -- end
+      -- Diagnostic Config
+      -- See :help vim.diagnostic.Opts
+      vim.diagnostic.config {
+        severity_sort = true,
+        float = { border = 'rounded', source = 'if_many' },
+        underline = { severity = vim.diagnostic.severity.ERROR },
+        signs = vim.g.have_nerd_font and {
+          text = {
+            [vim.diagnostic.severity.ERROR] = '󰅚 ',
+            [vim.diagnostic.severity.WARN] = '󰀪 ',
+            [vim.diagnostic.severity.INFO] = '󰋽 ',
+            [vim.diagnostic.severity.HINT] = '󰌶 ',
+          },
+        } or {},
+        virtual_text = {
+          source = 'if_many',
+          spacing = 2,
+          format = function(diagnostic)
+            local diagnostic_message = {
+              [vim.diagnostic.severity.ERROR] = diagnostic.message,
+              [vim.diagnostic.severity.WARN] = diagnostic.message,
+              [vim.diagnostic.severity.INFO] = diagnostic.message,
+              [vim.diagnostic.severity.HINT] = diagnostic.message,
+            }
+            return diagnostic_message[diagnostic.severity]
+          end,
+        },
+      }
 
       -- LSP servers and clients are able to communicate to each other what features they support.
       --  By default, Neovim doesn't support everything that is in the LSP specification.