xaxl / yaxl args for formatting axis tick labels

[grantmcdermott]

Closes #362.

Examples:

pkgload::load_all("~/Documents/Projects/tinyplot")
#> ℹ Loading tinyplot

plt(I(decrease/100) ~ treatment, OrchardSprays, main = "No label formatting")

plt(I(decrease/100) ~ treatment, OrchardSprays, main = "With label formatting",
    xaxl = tolower, yaxl = "percent")

#works well with themes
tinytheme('clean')
plt(I(decrease/100) ~ treatment, OrchardSprays, main = "With label formatting",
    xaxl = tolower, yaxl = "percent")

plt(GNP ~ Year, longley, type = "area", yaxl = "dollar")

# also works with functions from the scales package
plt(
  I(Sepal.Length*1e4) ~ Petal.Length | Species, facet = "by", data = iris,
  yaxl = scales::label_log(), log = "y"
)

^{Created on 2025-04-06 with reprex v2.1.1}