Add support for repeated sequences

[Mikaayenson]

Resolves #57

Details

Updated the grammar and added sample test case to support repeated sequences.

[rw-access]

Hi @Mikaayenson! It's exciting to see you dive right in to this issue. I think there are some more pieces that this is missing before it's ready to make sure all the edge cases are covered:

• should only work with the Elasticsearch syntax on. otherwise, it should remain a syntax error (in Endgame mode)
• it accidentally added new syntax sequence with runs=2 [ A ] [ B ]
• this is now valid syntax: sequence [ A ] with runs=2 in Elasticsearch mode, but is not for Endgame mode
• I think the AST should be expanded when the new syntax encountered: sequence [ A ] with runs=10 into sequence [ A ] [ A ] [ A ] [ A ] [ A ] [ A ] [ A ] [ A ] [ A ] [ A ]
• more tests to confirm the behavior is matching what's expected

If you want to see an example of how those flags are handled, check out #59 or some of the other PRs that add Elasticsearch syntax handling behind the flag. I'm happy to sync up and go over anything in the code base if you need. Feel free to DM me (on ela.st/slack or zoom).

[rw-access]

wow, nice turnaround! that was fast. 🏃‍♂️
just a few nits and I think a couple of tests needed, looks really good so far

[Mikaayenson]

@rw-access Thanks for the code walkthrough and feedback! I think it should be good to go now. 🤞

[rw-access]

LGTM, just a few small tweaks

[brokensound77]

Nice job! I left a few comments

Pending resolution to @brokensound77's comments

[brokensound77]

two small changes, then LGTM 🎉

[Mikaayenson]

Alright! Thanks @brokensound77. I think its ready to go, but ill wait until tomorrow just in case there's anything else.