markdown: set mkdnflow to conceal links

Co-Authored-by: iGor milhit <igor@milhit.ch>

lua/custom/plugins/mkdnflow.lua

@@ -16,6 +16,9 @@ return {
     lazy = true,
     config = function ()
       require('mkdnflow').setup({
+        links = {
+          conceal = true,
+        }
     })
     end
   }