Adjust different wording for missing argument

Author: olivroy

tests/testthat/test-with.R

@@ -1,7 +1,12 @@
 test_that("modify_defaults produces error with missing or incorrect defaults", {
-  lint_msg <- "`defaults` must be a named list"
-  expect_error(modify_defaults(), lint_msg, fixed = TRUE)
-  expect_error(modify_defaults("assignment_linter"), lint_msg, fixed = TRUE)
+  expect_error(
+    modify_defaults(),
+    "Missing required argument `defaults` should be a named list",
+    fixed = TRUE)
+  expect_error(
+    modify_defaults("assignment_linter"),
+    "`defaults` must be a named list",
+    fixed = TRUE)
 })
 
 test_that("linters_with_tags produces error with incorrect tags", {