Remove unused function from `struct rb_parser_config_struct`

ruby_parser.c

@@ -573,8 +573,6 @@ static const rb_parser_config_t rb_global_parser_config = {
     .enc_isascii = enc_isascii,
     .enc_mbc_to_codepoint = enc_mbc_to_codepoint,
 
-    .ractor_make_shareable = rb_ractor_make_shareable,
-
     .local_defined = local_defined,
     .dvar_defined = dvar_defined,
 

rubyparser.h

@@ -1371,9 +1371,6 @@ typedef struct rb_parser_config_struct {
     bool (*enc_isascii)(OnigCodePoint c, rb_encoding *enc);
     OnigCodePoint (*enc_mbc_to_codepoint)(const char *p, const char *e, rb_encoding *enc);
 
-    /* Ractor */
-    VALUE (*ractor_make_shareable)(VALUE obj);
-
     /* Compile */
     // int rb_local_defined(ID id, const rb_iseq_t *iseq);
     int (*local_defined)(ID, const void*);

universal_parser.c

@@ -214,8 +214,6 @@
 #define ENCODING_IS_ASCII8BIT   p->config->encoding_is_ascii8bit
 #define rb_usascii_encoding     p->config->usascii_encoding
 
-#define rb_ractor_make_shareable p->config->ractor_make_shareable
-
 #define rb_local_defined          p->config->local_defined
 #define rb_dvar_defined           p->config->dvar_defined