docs: add missing @return tags to exported functions

Add @return roxygen tags and corresponding \value Rd sections for:
- spark_bar(), spark_line() (R/spark.R)
- ruler() (R/ruler.R)
- simple_theme() (R/simple-theme.R)
- format_error(), format_warning(), format_message() (R/format-conditions.R)
- test_that_cli() (R/test.R)

Also fix typo in R/bullets.R: cli_format_bullets_raw() -> cli_bullets_raw()

R CMD check --as-cran requires \value for all exported functions.

Author: LeonidasZhak

R/bullets.R

@@ -70,7 +70,7 @@ cli_bullets <- function(
 
 #' List of verbatim items
 #'
-#' `cli_format_bullets_raw()` is similar to [cli_bullets()], but it does
+#' `cli_bullets_raw()` is similar to [cli_bullets()], but it does
 #' not perform any inline styling or glue substitutions in the input.
 #'
 #' `format_bullets_raw()` returns the output instead of printing it.

R/format-conditions.R

@@ -26,6 +26,7 @@
 #' @param message It is formatted via a call to [cli_bullets()].
 #' @param .envir Environment to evaluate the glue expressions in.
 #'
+#' @return A character string containing the formatted message.
 #' @seealso These functions support [inline markup][inline-markup].
 #' @family functions supporting inline markup
 #' @export

R/ruler.R

@@ -1,5 +1,7 @@
 #' Print the helpful ruler to the screen
 #'
+#' @return `NULL`, invisibly. Called for its side effect of printing a
+#'   ruler to the screen.
 #' @export
 #' @param width Ruler width.
 #' @examples

R/simple-theme.R

@@ -60,6 +60,7 @@
 #'   Detection usually works in recent RStudio versions, and in iTerm
 #'   on macOS, but not on other platforms.
 #'
+#' @return A named list that can be used as a cli theme.
 #' @seealso [themes], [builtin_theme()].
 #' @export
 

R/spark.R

@@ -34,6 +34,7 @@
 #' ```
 #'
 #' @param x A numeric vector between 0 and 1
+#' @return A character string of class `cli_spark_bar` and `cli_spark`.
 #' @export
 #' @seealso [spark_line()]
 
@@ -95,6 +96,7 @@ spark_bar_chars <- function(x, bars = NULL) {
 #' ```
 #'
 #' @inheritParams spark_bar
+#' @return A character string of class `cli_spark_line` and `cli_spark`.
 #' @export
 #' @seealso [spark_bar()]
 

R/test.R

@@ -41,6 +41,8 @@
 #'   * `"all"`: turn on all hyperlinks,
 #'   * `"none"`: turn off all hyperlinks.
 #'
+#' @return The return value of [testthat::test_that()] for the last
+#'   configuration tested (invisibly).
 #' @export
 #' @examples
 #' # testthat cannot record or compare snapshots when you run these