Remove unused functions from struct rb_parser_config_struct

ruby_parser.c

@@ -184,12 +184,6 @@ intern3(const char *name, long len, void *enc)
     return rb_intern3(name, len, (rb_encoding *)enc);
 }
 
-static VALUE
-enc_from_encoding(void *enc)
-{
-    return rb_enc_from_encoding((rb_encoding *)enc);
-}
-
 static int
 encoding_is_ascii8bit(VALUE obj)
 {
@@ -436,7 +430,6 @@ static const rb_parser_config_t rb_global_parser_config = {
     .enc_isspace = enc_isspace,
     .enc_coderange_7bit = ENC_CODERANGE_7BIT,
     .enc_coderange_unknown = ENC_CODERANGE_UNKNOWN,
-    .enc_from_encoding = enc_from_encoding,
     .encoding_is_ascii8bit = encoding_is_ascii8bit,
     .usascii_encoding = usascii_encoding,
     .enc_coderange_broken = ENC_CODERANGE_BROKEN,