Review `{cli}` usage

[Ilia-Kosenkov]

It seems that in one of the recent updates {cli} was significantly modified. Among all the changes (which introduced issues in snapshot tests), there are a few (new?) functions I'd like to draw your attention to:

• cli::cli_bullets This function accepts a named character vector of messages that are then glue-interpolated and printed. Vector names are used to determine the symbol at the beginning, i.e. *, >, !, etc. We could now aggregate our detail messages (in ui_throw or similar functions) using cli_bullets. We can even make something like this:

  bullets <- function(...) {
  cli::cli_format_method(unlist(rlang::list2(...)))
  }

  which will work as bullets(`*` := "Text 1", `!` := "Text 2 with {.strong interpolation}").

• cli::test_that_cli, which allows configuring {testthat} and styles of {cli} for the duration of test.

It may be worth investigating if any of these functions can be (later) used in {rextendr}.

[Ilia-Kosenkov]

Closing because {cli} usage has been improved in one of the old PRs and is now rather mature.