better completion for objects

[ghost]

Currently completion for object methods only seems to work once you start typing a method name after #. This isn't as useful as completion for records because you need to know at least the first character of the method name.

This seems to be an issue with merlin although I'm not sure why. However, we should be able to work around it by detecting when # is typed and first reconstructing the initial list of methods from the inferred type.

[ghost]

It looks like the emacs mode does support completion for methods but I think it uses something special to achieve it, maybe similar to how completion for labels works. I get this impression because when completing methods, they do not show up in the usual company-mode pulldown but are listed in a separate buffer, just like completion for labels.