Unquoted identifiers naming rule is incorrect

The naming rule is in https://dev.mysql.com/doc/refman/8.0/en/identifiers.html

The rule for unquoted identifiers is incorrect.
* ASCII: [0-9,a-z,A-Z$_] (basic Latin letters, digits 0-9, dollar, underscore)
* Extended: U+0080 .. U+FFFF

In the following test, we can see that `@` is unpermitted
https://github.com/sqlparser-rs/sqlparser-rs/blob/44727891713114b72546facf21a335606380845a/tests/sqlparser_mysql.rs#L1661

I think we need to fix the unquoted identifiers for MYSQL and HIVE
https://github.com/sqlparser-rs/sqlparser-rs/blob/44727891713114b72546facf21a335606380845a/src/tokenizer.rs#L803-L811

MYSQL
https://github.com/sqlparser-rs/sqlparser-rs/blob/44727891713114b72546facf21a335606380845a/src/dialect/mysql.rs#L28-L41

HIVE
https://github.com/sqlparser-rs/sqlparser-rs/blob/44727891713114b72546facf21a335606380845a/src/dialect/hive.rs#L28-L36

Comece pelo teste de MySQL próximo de tests/sqlparser_mysql.rs:1661, depois leia a lógica de identificadores sem aspas em src/tokenizer.rs:803-811 e as definições dos dialetos MYSQL e HIVE. Atualize a cobertura das regras para ambos os dialetos e adicione ou ajuste testes para que @ seja rejeitado e os intervalos ASCII e estendidos documentados sejam aceitos.

Escrita pelo modelo de indexação a partir do texto da issue.