Partially closes #318. Builds on the same repel.R function that was introduced in the direct labels PR (#589)

pkgload::load_all("~/Documents/Projects/tinyplot")
#> ℹ Loading tinyplot
tinyplot(mpg ~ wt, data = mtcars,
  type = type_text(labels = row.names(mtcars), xpd = NA))

versus

tinyplot(mpg ~ wt, data = mtcars,
  type = type_text(labels = row.names(mtcars), xpd = NA, repel = TRUE))

Two limitations:

1. We don't adjust the plot region and margins in response to the text width or height, so these can overflow the plot/device region (but that's a pre-existing issue).

2. The repulsion logic operates at the group level. So, while we can guarantee that text will be dodged within groups, there may still be overlaps across groups. (Fixing this requires a more heavy-handed change to the code and will likely necessitate a second pass through the main tinyplot.R code. So I'm not sure it's worth it.)

tinyplot(mpg ~ wt | factor(cyl), data = mtcars,
  type = type_text(labels = row.names(mtcars), xpd = NA, repel = TRUE, ))

^{Created on 2026-06-10 with reprex v2.1.1}