Support Struct datatype parsing for GenericDialect

[duongcongtoai]

Current BigQueryDialect is capable of parsing struct data type such as

create table t (s struct<n int, s varchar>);

According to README, this feature should also support GenericDialect, however in current code, before parsing this syntax, we only allow BigQueryDialect to have this syntax

[jayzhan211]

Can we also support syntax with '()', like create table t (s struct(n int, s varchar)); like duckdb

[duongcongtoai]

https://github.com/sqlparser-rs/sqlparser-rs/blob/2f437db2a68724e4ae709df22f53999d24804ac7/src/parser/mod.rs#L1903
Then i think we can add | LParen here

[alamb]

@duongcongtoai filed #1245 as a follow on. THank you