feat: `resolve_id()` should be exported

[schloerke]

Hi @gadenbuie , i'll try to write an example this week. The code works if i put everything in app.py, so I think the logic should be fine. Also, I've now got it to work by using resolve_id() so I am pretty sure it's a namespace issue. So it works for now, but since resolve_id is defined in the _namespaces folder, I don't think that's what I'm supposed to do :)

Originally posted by @ME-researchgroup in #1303

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Similarly, examples for creating components for bookmarks would be misleading if resolve_id() isn't exposed

Related #1870

[schloerke]

@ME-researchgroup ; TIL... Turns out, resolve_id is already exported! (~3 yrs ago: https://github.com/posit-dev/py-shiny/blame/22634c93320622f638130d5939831edfceaa06c2/shiny/module.py)

shiny.module.resolve_id

Related comment: #1303 (comment)