Add tests parsing/generating msg/srv/action comments with non-ASCII characters

[gavanderhoorn]

As discussed in ros2/rcl_interfaces#147:

[..] tests for non-ascii characters in comments in message files [..]

should be added to the appropriate packages.

ros2/rcl_interfaces#147 removed a couple of unicode apostrophes, which could be seen as having been:

[tests for] support [of] Unicode inside of comments in .msg files [..]

As those characters were removed in ros2/rcl_interfaces#147, proper tests should be added here in ros2/rosidl to replace them.

[guichristmann]

I'd like to try this if no else has yet.

Would it be enough to add a new test file under rosidl_adapter e.g. test_parse_message_with_unicode_comments.py in similar style to the other tests there and make sure the parser can handle comments with unicode characters? Appreciate if you could provide more context that I might be missing.

[clalancette]

Yes, I think that would be the best thing. Add a new test file into rosidl_adapter that tests out unicode comments. Thanks for taking this on!