Use category: :deprecated in warnings that are related to deprecation

Also document that both :deprecated and :experimental are supported
:category option values.

The locations where warnings were marked as deprecation warnings
was previously reviewed by shyouhei.

Comment a couple locations where deprecation warnings should probably
be used but are not currently used because deprecation warning
enablement has not occurred at the time they are called
(RUBY_FREE_MIN, RUBY_HEAP_MIN_SLOTS, -K).

Add assert_deprecated_warn to test assertions.  Use this to simplify
some tests, and fix failing tests after marking some warnings with
deprecated category.

1 files changed, 1 insertions, 1 deletions

diff --git a/array.c b/array.c
index 207d5a337a..f4c3e27af7 100644
--- a/array.c
+++ b/array.c
@@ -2835,7 +2835,7 @@ rb_ary_join_m(int argc, VALUE *argv, VALUE ary)
     if (rb_check_arity(argc, 0, 1) == 0 || NIL_P(sep = argv[0])) {
         sep = rb_output_fs;
         if (!NIL_P(sep)) {
-            rb_warn("$, is set to non-nil value");
+            rb_category_warn(RB_WARN_CATEGORY_DEPRECATED, "$, is set to non-nil value");
         }
     }