Expose position argument for `geom_range()`

[willgearty]

This exposes the position argument for geom_range() so you can do something like the following:

library(ggplot2)
library(ggtree)
library(treeio)
library(deeptime)

file <- system.file("extdata/BEAST", "beast_mcc.tree", package="treeio")
beast <- read.beast(file)

ggtree(beast, position = position_nudge(x = -500))  +
  geom_range(range='length_0.95_HPD', color='red', alpha=.6, size=2,
                  position = position_nudge(x = -500)) +
  scale_x_continuous(breaks = seq(-500, -460, 10), labels = abs(seq(-500, -460, 10))) +
  theme_tree2() +
  coord_geo(pos = list("bottom", "bottom"), dat = list("stages", "periods"),
            neg = TRUE, ylim = c(0, NA), center_end_labels = TRUE, abbrv = list(TRUE, FALSE))

This is particularly useful for plotting trees that are made up of entirely extinct taxa which you need to bump backwards in time (since ggtree puts the root at 0).