Fix rb_interned_str: create strings with BINARY (akak ASCII_8BIT) encoding

[Bug #21842]

The documentation always stated as much, and it's consistent with the
rb_str_* family of functions.

1 files changed, 1 insertions, 1 deletions

diff --git a/string.c b/string.c
index 6f4ea03fb3..d564c2e2e1 100644
--- a/string.c
+++ b/string.c
@@ -12709,7 +12709,7 @@ VALUE
 rb_interned_str(const char *ptr, long len)
 {
     struct RString fake_str = {RBASIC_INIT};
-    return register_fstring(setup_fake_str(&fake_str, ptr, len, ENCINDEX_US_ASCII), true, false);
+    return register_fstring(setup_fake_str(&fake_str, ptr, len, ENCINDEX_ASCII_8BIT), true, false);
 }
 
 VALUE