xaxl/yaxl symbol shortcuts

[grantmcdermott]

This PR would allow users to pass the equivalent symbol as a(n even shorter) shortcut to xaxl/yaxl. For example, "percent" <=> "%", "dollar" <=> "$", etc.

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

dat = data.frame(
  x = rnorm(100, 1e3, 50),
  y = rnorm(100, 1e3, 10)
)
plt(y ~ x, dat, xaxl = "€", yaxl = "$")

plt(y ~ I(x/1e4), dat, xaxl = "%", yaxl = ",")

tinytheme()

^{Created on 2025-04-10 with reprex v2.1.1}

Thoughts?

[vincentarelbundock]

I like this A LOT but think we should remove the long shortcuts to avoid duplication and confusion.

[grantmcdermott]

Ha, the Vincent "anti-aliasing" principle strikes again!

In seriousness, though I wouldn't want to replace the longer strings. Personally, I'm comfortable keeping both options. Let's see what Achim says...

[zeileis]

I have to confess that I also like the idea with the shortcuts and would keep both versions - the short symbol and the long text version.

If we only keep one of the two, I would keep the long text version (and not the short symbol).

[grantmcdermott]

Majority rules ;-)