have successive beds identical facies?
Examples
s = as_stratcol(c(0.5, 1, 0.3, 0.7), c("sand", "shale", "sand", "shale"), L_unit = "m")
facies_repetitions(s) # returns FALSE
#> [1] FALSE
s = as_stratcol(c(0.5, 1, 0.3, 0.7), c("sand", "sand", "shale", "shale"), L_unit = "m")
facies_repetitions(s) # returns TRUE
#> [1] TRUE