perf(markdown): only run markdownlint-cli2 formatter when there are markdownlint diagnostics for the buffer

lua/lazyvim/plugins/extras/lang/markdown.lua

@@ -24,6 +24,14 @@ return {
             end
           end,
         },
+        ["markdownlint-cli2"] = {
+          condition = function(_, ctx)
+            local diag = vim.tbl_filter(function(d)
+              return d.source == "markdownlint"
+            end, vim.diagnostic.get(ctx.buf))
+            return #diag > 0
+          end,
+        },
       },
       formatters_by_ft = {
         ["markdown"] = { "prettier", "markdownlint-cli2", "markdown-toc" },