Snowflake: support for extended column options in CREATE TABLE

[7phs]

Snowflake supports several extended options for column definitions:

-- Column definition
    <col_name> <col_type>
      [ inlineConstraint ]
      [ NOT NULL ]
      [ COLLATE '<collation_specification>' ]
      [
        {
          DEFAULT <expr>
          | { AUTOINCREMENT | IDENTITY }
            [
              {
                ( <start_num> , <step_num> )
                | START <num> INCREMENT <num>
              }
            ]
            [ { ORDER | NOORDER } ]
        }
      ]
      [ [ WITH ] MASKING POLICY <policy_name> [ USING ( <col_name> , <cond_col1> , ... ) ] ]
      [ [ WITH ] PROJECTION POLICY <policy_name> ]
      [ [ WITH ] TAG ( <tag_name> = '<tag_value>' [ , <tag_name> = '<tag_value>' , ... ] ) ]
      [ COMMENT '<string_literal>' ]

This merge request implements support for these additional column options.

[iffyio]

@7phs just a couple comments and I think this looks good!

[iffyio]

LGTM! cc @alamb

[alamb]

Thanks @7phs and @iffyio

[coveralls]

Pull Request Test Coverage Report for Build 11391429828

Warning: This coverage report may be inaccurate.

This pull request's base commit is no longer the HEAD commit of its target branch. This means it includes changes from outside the original pull request, including, potentially, unrelated coverage changes.

• For more information on this, see Tracking coverage changes with pull request builds.
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• For a quick fix, rebase this PR at GitHub. Your next report should be accurate.

Details

• 279 of 284 (98.24%) changed or added relevant lines in 6 files are covered.
• 1410 unchanged lines in 6 files lost coverage.
• Overall coverage increased (+0.07%) to 89.392%

---

Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/dialect/snowflake.rs	55	56	98.21%
src/parser/mod.rs	14	15	93.33%
tests/sqlparser_mssql.rs	11	12	91.67%
src/ast/ddl.rs	39	41	95.12%

Files with Coverage Reduction	New Missed Lines	%
tests/sqlparser_mssql.rs	1	93.38%
src/lib.rs	3	12.2%
src/tokenizer.rs	49	94.14%
src/ast/mod.rs	394	82.44%
src/parser/mod.rs	411	93.39%
tests/sqlparser_common.rs	552	89.58%

Totals
Change from base Build 11239696437:	0.07%
Covered Lines:	30428
Relevant Lines:	34039

---

💛 - Coveralls