Problems with UNIQUE parsing

[cfhowes]

There appears to be a couple of problems with UNIQUE parsing.

1. simple-ddl-parser/tests/test_simple_ddl_parser.py

   Line 365 in f605740

   unique ("id", "title")

   I believe that this test is incorrect. The output should not have UNIQUE on the individual columns, but rather should have an entry in constraints.uniques with both columns listed in the columns. See https://www.mysqltutorial.org/mysql-basics/mysql-unique-constraint/#:~:text=To%20define%20a%20UNIQUE%C2%A0%20constraint%20for%20two%20or%20more%20columns%2C%20you%20use%20the%20following%20syntax%3A
2. UNIQUE KEY statements currently cause the entire table to be ignored. IE UNIQUE KEY "fun_unique_key" ("fun_unique_column"), In this case I think we'd like a single column to parse into a column UNIQUE statement, and multiple columns to parse into the constraints.uniques location.