Adapt to single indent semantics in style guide

[krlmlr]

https://style.tidyverse.org/functions.html#multi-line-function-definitions

It's merely a start, doesn't capture all edge cases yet.

Doesn't conflict with #1137 except for the currently last commit that would be easy to do later on.

CC @MichaelChirico.

[github-actions]

This is how benchmark results would change (along with a 95% confidence interval in relative change) if 8b9a4a0 is merged into main:

• ✔️cache_applying: 166ms -> 168ms [-2.56%, +5.29%]
• ✔️cache_recording: 521ms -> 520ms [-0.83%, +0.42%]
• ✔️without_cache: 998ms -> 996ms [-1.16%, +0.57%]

Further explanation regarding interpretation and methodology can be found in the documentation.

[IndrajeetPatil]

The changes look good from my end. If you want, you can also add tests for anonymous function and nested function cases for a good measure.

library(styler)

"purrr::map(vec, function(
    x
) NULL)" -> code1

style_text(code1)
#> purrr::map(vec, function(
#>   x
#> ) {
#>   NULL
#> })

"function(
    x,
    f = function(
    x
    ) (x)^2
) NULL" -> code2

style_text(code2)
#> function(
#>   x,
#>   f = function(
#>     x
#>   ) {
#>     (x)^2
#>   }
#> ) {
#>   NULL
#> }

^{Created on 2024-10-23 with reprex v2.1.1}

---

Outside the scope of the current PR, but this looks a bit off:

function(
  x,
  y) {
  NULL
}

compared to

function(
  x,
  y
) {
  NULL
}

I don't know if the style guide has changed its opinion on supporting the latter in the latest round of updates, though.

[MichaelChirico]

Oh, just realized I'm cc'd. test output LGTM. I might like some cases with comments, especially comments in weird places like

f = function(
a
# comment
= 1
) { a }