Regression in 1.40 and 1.41 in support of -- in options
This old chestnut again: https://gitlab.com/esr/src/-/issues/32
```
$ src diff 21-22 -- todo.org
src: -- is not registered
$ src version
src: 1.41
python: 3.13.5
RCS: 5.10.1
platform: linux
```
also in 1.40
issue