filter_slider should default to round = TRUE when the column is an integer

[EDAlnor]

Hi, experienced R user here, but first time ever posting on github, so please excuse any errors and just let me know if I am not following conventions.

I'm using crosstalk with plot_ly. If the column I provide as filter_slider is an integer, it seems logical to me that decimals should not be shown, i.e., its verbose that I have to provide round = T as an option.

For example in:

library(plotly)
library(dplyr)
library(crosstalk)

df <- data.frame(
  area  = rep(c('a', 'b', 'c'), 3),
  value = runif(9, min = 0, max =10),
  year  = as.integer(c(1,1,1,2,2,2,3,3,3))
) %>% highlight_key()

widget <- filter_slider(id = 'year', label = 'Year', dfk, ~mnum)

bscols(
  widget,
  plot_ly(df, x = ~year, y = ~value) %>% add_lines(color = ~area)
)

...the slider lets me select 6.5, 4.2, and so on, which shouldn't be possible given that year is an integer.