Formats p-values according to common scientific conventions. Values less than 0.001 are formatted as "<0.001".
Examples
format_pvalue(0.0005, digits = 3) # Returns "<0.001"
#> [1] "<0.001"
format_pvalue(0.0234, digits = 3) # Returns "0.023"
#> [1] "0.023"
format_pvalue(c(0.0005, 0.0234, 0.4567), digits = 3)
#> [1] "<0.001" "0.023" "0.457"
# Returns c("<0.001", "0.023", "0.457")