[SIG-13647] allow idents for limits and offsets - #3

* cargo fmt

* add json index for snowflake, bq

* add flatten

* add snowflake dateparts

* useful parsing errors

* parse decimals without 0 prefix

* snowflake: within group

* snowflake: json bracket syntax

* snowflake: join where

* snowflake: ilike

* snowflake: handle like ... escape ...

* snowflake: try_cast

* snowflake: qualify

* snowflake: handle pivot

* snowflake: allow idents to start with $

* snowflake: fix parsing for position

* snowflake: minus set operator

* snowflake json: cleanup/fix bracket and dot notation

* snowflake: number

* snowflake: string literal parse esc quotes

* snowflake: nested exprs can be lists

* join constraints are not required

* smarter number literal parsing with state machine for scientific notation

* snowflake: date/time field variants

* rs/pg: AT TIME ZONE

* rs: ignore/respect nulls

* tokenizer: treat zwsp as whitespace

* pg/rs: SIMILAR TO

* rs: allow brackets around idents

* rs: allow str literal date/time parts

* rs: more IS [NOT] *

* pg: add json ops

* add BigQueryDialect

* bq: backtick quoted idents

* bq: be resilient to trailing commas

* bq: be much more flexible with parsing function args

* bq: handle idents using backticks

* bq: handle interval parsing

* bq: parse regex literals (consider merging with snowflake str parsing)

* bq: add in more date/time parts

* bq: allow aliases with backtick quoting

* bq: parse wildcard modifiers except/replace

* bq: named window specs

* bq: IN <expr>

* snowflake: remove special position handling? maybe should remove more

* bq: double quoted string

* bq: typeless structs

* bq: add secret datetime fields

* fixup bq args bs

* snowflake: ignore/respect nulls for window funcs

* Added Unpivot. Fixed some Pivot (#2)

-- Technically, unpivot has some stricter
   expr requirements (eg instead of expr for ident in col_list
   it should be <column> for ident in col_list). I haven't been
   able to navigate to find this stricter definition yet, but
   maybe we want this fix ASAP.

* [SIG-13647] allow idents for limits and offsets (#3)

* Fix compilation issues (#5)

* Use enum to prevent &'static str lifetime issues

-- Could also use `serde(bound(deserialize = "'de: 'static"))`
-- But I think that will need to be applied on all structs
-- that depend on Expr... which I assume will be ubiquitous

* Make WindowSpec serializable

* Fix more static str stuff

* Fixed tests

* Fixed all compilation errors

* Run clippy --fix

* Fixd lint errors

* Fix more lint errors

* Fix remaining lint issues

* Fix tests pass (#7)

* Fixed trivial tests failures

* Fixed more tests

* Ignored backcompat breaks... for now

* More simple tests fixes

* Fixed tests... but not sure whether this is right

* Clippy

* cargo fmt

* Fixed regression #1

* Fixed second regression

* Ignore snowflake numeric failing test

* Added tests for sigma-related parser changes (#8)

* Added regression tests

* Added test for sigma-related parser changes

* Amended comments

* Removed extraneous println

* Fixed build errors part 1

* Manual cargo fmt because it's hanging on my machine

* When you fail at %s

Co-authored-by: Mark Wong Siang Kai <markwongsk@gmail.com>