Update JoinClauseMixin to support more ANSI SQL joins

[griffio]

🦶Initial step to support cashapp/sqldelight#5086

Add Ansi Sql join operators RIGHT and FULL e.g Now supported in https://www.sqlite.org/releaselog/3_39_0.html

LATERAL modifier not included, as works in two different ways (table/subquery and join) and should be implemented as a separate feature

These are added as forward declarations in the SqlLexer.flex that are needed for dialects to override

🏰 Keep core grammar with LEFT join

This allows the existing dialects to work with LEFT join and enables dialects to add RIGHT, FULL where supported, e.g PostgreSql and latest Sqlite dialect

e.g Postgresql.bnf would override the core join_operator and adds right_join_operator

📸 Tested snapshot build with SqlDelight branch as this appears to work

join_operator ::= ( COMMA
                  | [ NATURAL ] [ ( {left_join_operator} | {right_join_operator} | {full_join_operator} ) [ OUTER ] | INNER | CROSS ] JOIN ) {
  extends = "com.alecstrong.sql.psi.core.psi.impl.SqlJoinOperatorImpl"
  implements = "com.alecstrong.sql.psi.core.psi.SqlJoinOperator"
  override = true
}

[hfhbd]

Keep core grammar with LEFT join
This allows the existing dialects to work with LEFT join and enables dialects to add RIGHT, FULL where supported, e.g PostgreSql and latest Sqlite dialect

This was on purpose? Then we should revert #618, I didn't know some dialects do not support ANSI RIGHT or FULL...

[griffio]

Keep core grammar with LEFT join
This allows the existing dialects to work with LEFT join and enables dialects to add RIGHT, FULL where supported, e.g PostgreSql and latest Sqlite dialect

This was on purpose? Then we should revert #618, I didn't know some dialects do not support ANSI RIGHT or FULL...

Yes - see https://www.sqlite.org/releaselog/3_39_0.html

• SQLite Release 3.39.0 On 2022-06-25
• Add (long overdue) support for RIGHT and FULL OUTER JOIN.

This was a way that the core grammar can be overridden easier by supporting dialects that have all joins (mysql doesn't support FULL)