Add a filter that allows everything

[vjackson725]

One feature which is common in file pickers is to have a filter that doesn't actually filter anything. This usually is the last filter, used in case the user wants to load a file the application isn't expecting.

This features does not appear possible using this library. I suggest changing the add_filter to take an optional list, or making a new structure for filters, which a to-string list can be .into()'ed into.

[IohannRabeson]

I have the same need. To me if the user never calls add_filter then the filtering should be disabled and everything should be visible.
@PolyMeilex What do you think about that? Is there any reasons for filtering all the files by default? Would you be interested if I try to change this behavior?
Another question, I'm having the issue on Windows but maybe it's not the same for other plateforms?
Oh I see for Windows I can use the filter "*" to get everything (see example in https://learn.microsoft.com/en-us/windows/win32/api/shobjidl_core/nf-shobjidl_core-ifiledialog-setfiletypes) but will it work for other plateforms?

[PolyMeilex]

To me if the user never calls add_filter then the filtering should be disabled and everything should be visible.

Sounds reasonable, I agree. The fact that it does not act like this is a bug IMO.

[PolyMeilex]

You have not stated your platform, so I'll have to assume that fixing it on Windows in #224 fixed it for you.
Reopen if you are on a different platform, and it's still broken there.