Show where mutated chilled strings were allocated

[Feature #20205]

The warning now suggests running with --debug-frozen-string-literal:

```
test.rb:3: warning: literal string will be frozen in the future (run with --debug-frozen-string-literal for more information)
```

When using --debug-frozen-string-literal, the location where the string
was created is shown:

```
test.rb:3: warning: literal string will be frozen in the future
test.rb:1: info: the string was created here
```

When resurrecting strings and debug mode is not enabled, the overhead is a simple FL_TEST_RAW.
When mutating chilled strings and deprecation warnings are not enabled,
the overhead is a simple warning category enabled check.

Co-authored-by: Jean Boussier <[email protected]>
Co-authored-by: Nobuyoshi Nakada <[email protected]>
Co-authored-by: Jean Boussier <[email protected]>

Author: 3 people

command_line/fixtures/debug_info.rb

@@ -1,4 +1,3 @@
-# frozen_string_literal: true
 a = 'string'
 b = a
 c = b

command_line/frozen_strings_spec.rb

@@ -57,9 +57,18 @@
 
 describe "The --debug flag produces" do
   it "debugging info on attempted frozen string modification" do
-    error_str = ruby_exe(fixture(__FILE__, 'debug_info.rb'), options: '--debug',  args: "2>&1")
+    error_str = ruby_exe(fixture(__FILE__, 'debug_info.rb'), options: '--enable-frozen-string-literal --debug',  args: "2>&1")
     error_str.should include("can't modify frozen String")
     error_str.should include("created at")
-    error_str.should include("command_line/fixtures/debug_info.rb:2")
+    error_str.should include("command_line/fixtures/debug_info.rb:1")
+  end
+
+  guard -> { ruby_version_is "3.4" and !"test".frozen? } do
+    it "debugging info on mutating chilled string" do
+      error_str = ruby_exe(fixture(__FILE__, 'debug_info.rb'), options: '-w --debug',  args: "2>&1")
+      error_str.should include("literal string will be frozen in the future")
+      error_str.should include("the string was created here")
+      error_str.should include("command_line/fixtures/debug_info.rb:1")
+    end
   end
 end