Support `person()` object containing multiple `email`s

[jmbarbone]

I'm hitting an error propagating up through devtools::document().

==> devtools::document(roclets = c('rd', 'collate', 'namespace'))

ℹ Updating package documentation
ℹ Loading package
Error in `map_chr()`:
ℹ In index: 1.
Caused by error:
! Result must be length 1, not 2.
Backtrace:
     ▆
  1. ├─base::suppressPackageStartupMessages(...)
  2. │ └─base::withCallingHandlers(expr, packageStartupMessage = function(c) tryInvokeRestart("muffleMessage"))
  3. ├─devtools::document(roclets = c("rd", "collate", "namespace"))
  4. │ └─roxygen2::roxygenise(pkg$path, roclets)
  5. │   └─base::lapply(blocks, block_set_env, env = env)
  6. │     └─roxygen2 (local) FUN(X[[i]], ...)
  7. │       └─roxygen2:::block_find_object(block, env)
  8. │         ├─roxygen2:::object_defaults(object, block)
  9. │         └─roxygen2:::object_defaults.package(object, block)
 10. │           └─roxygen2:::package_authors(desc$get_field("Authors@R", NULL))
 11. │             └─purrr::map_chr(unclass(authors), author_desc)
 12. │               └─purrr:::map_("character", .x, .f, ..., .progress = .progress)
 13. │                 ├─purrr:::with_indexed_errors(...)
 14. │                 │ └─base::withCallingHandlers(...)
 15. │                 └─purrr:::call_with_cleanup(...)
 16. └─base::.handleSimpleError(...)
 17.   └─purrr (local) h(simpleError(msg, call))
 18.     └─cli::cli_abort(...)
 19.       └─rlang::abort(...)
Execution halted

Exited with status 1.

There's an issue with parsing a person object containing multiple emails

me <- person("me", email = c("one@email.me", "two@email.me"))
print(me)
#> [1] "me <one@email.me, two@email.me>"
# internal returns character(2), which map_chr() is not expecting
roxygen2:::author_desc(unclass(me)[[1]])
#> [1] "me \\email{one@email.me}" "me \\email{two@email.me}"

^{Created on 2023-06-09 with reprex v2.0.2}

paste0() here is recycling:

roxygen2/R/object-package.R

Lines 53 to 55 in a34bdf7

	if (!is.null(x$email)) {
	desc <- paste0(desc, " \\email{", x$email, "}")
	}

[hadley]

Want to do a PR? Looks like it would be a relatively simple fix.