inst/examples/shiny_example missing

[lianos]

I was poking around the codebase to see if there was any guidance on how to respond to plotly hover, click, etc. events when using iheatmapr with shiny.

I landed on the ?iheatmapr_event man page, which alludes to having an exemplar shiny app in its Examples section:

## Not run: 
shiny::runApp(system.file("examples", "shiny_example", package = "iheatmapr"))
## End(Not run)

But it seems that the inst/examples/shiny_example was nuked, or never made its way into the repo.

I do see that there is some code to take inspiration from in the test_iheatmapr_event() function found in R/shiny_test.R.

I'm happy to provide a small PR to nuke the Examples section from the iheatmapr_event help page and perhaps put a @seealso test_iheatmapr_event, or put a reference to that function elsewhere.

Alternatively if the inst/examples/shiny_example directory existed in one of the dev's computers but just never got added to the repo, perhaps they can be dropped in?