Give result of initial_time_split() its own subclass

[hfrick]

library(rsample)

initial_split(mtcars) |> class()
#> [1] "initial_split" "mc_split"      "rsplit"

# extra subclass to "initial_split"
group_initial_split(mtcars, cyl) |> class()
#> [1] "group_initial_split" "initial_split"       "grouped_mc_split"   
#> [4] "mc_split"            "rsplit"

# should also get its own subclass
initial_time_split(mtcars) |> class()
#> [1] "initial_split" "rsplit"

^{Created on 2022-12-06 with reprex v2.0.2}

[github-actions]

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