Add desired improvements (link to issues) and troubleshooting (no, really, use python3)

to readme

README.md

@@ -19,3 +19,22 @@ python3 pomodoroprompt.py
 ```
 
 See the `logs/` folder for daily, one-pomodoro-at-a-time time logs.
+
+## Desired improvements
+
+Too many to write down.  Suggest your own:
+
+https://gitlab.com/agaric/pomodoroprompt/-/issues
+
+## Troubleshooting
+
+If you run `python pomodoroprompt.py` and get:
+
+```
+  File "pomodoroprompt.py", line 85
+    print('\r', str_minutes(to_go), sep='', end='')
+                                       ^
+SyntaxError: invalid syntax
+```
+
+You need to specify Python 3: `python pomodoroprompt.py`