there are words which nextcloud would call illegal that this system wouldn't

which is fair. But I have no ability to be sure I have all the necessary characters.

ShowHandler.cs

@@ -60,7 +60,8 @@ namespace director
             Directory.CreateDirectory(outputPath);
 
             checklistFilename = $"checklist ({todo.Occurrence._event.Summary}).md";
-            foreach (char c in System.IO.Path.GetInvalidFileNameChars())
+            var invalidFilenames = System.IO.Path.GetInvalidFileNameChars().Concat(new char[] {'(', ')', ':'});
+            foreach (char c in invalidFilenames)
             {
                 checklistFilename = checklistFilename.Replace(c, '_');
             }
@@ -68,17 +69,6 @@ namespace director
             Console.WriteLine($"checklistFilename: {checklistFilename}");
 
             WriteChecklist();
-            // don't actually know how to share via webdav. But also nextcloud doesn't seem to cooperate anyway.
-            // #region share with humans
-            // if (todo.Configuration.checklist?.FirstOrDefault(pl => pl.type == LineType.manual) != null)
-            // {
-            //     Console.WriteLine($"nothing manual, not sharing with humans.");
-            // }
-            // else
-            // {
-            //     //TODO: share
-            // }
-            // #endregion
         }
         private void WriteChecklist()
         {
@@ -91,6 +81,10 @@ namespace director
                 {
                     text.Append("* [ ] ");
                 }
+                else
+                {
+                    text.AppendLine();
+                }
                 text.AppendLine($"{line.description}");
             }
             File.WriteAllText(checklistFilename, text.ToString());