Refactor list syntax

[chenzhiguang]

benchmark before

benchmark after

[chenzhiguang]

The smoke test fails. I will check that.

[coveralls]

Pull Request Test Coverage Report for Build 3585947176

• 88 of 90 (97.78%) changed or added relevant lines in 9 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage increased (+1.04%) to 95.662%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
lib/src/block_syntaxes/list_syntax.dart	49	51	96.08%
<!--	Total:	88	90	97.78%	-->

Totals
Change from base Build 3577213587:	1.04%
Covered Lines:	1279
Relevant Lines:	1337

---

💛 - Coveralls

[kevmoo]

@chenzhiguang – we'll have to do the same dance w/ flutter_markdown again. Want to send a PR there?

[chenzhiguang]

@chenzhiguang – we'll have to do the same dance w/ flutter_markdown again. Want to send a PR there?

PR is ready: https://github.com/flutter/packages/pull/2862

[kevmoo]

@srawlins – we're green on Flutter markdown!

[chenzhiguang]

@srawlins Hi, I am waiting for these two latest PRs get revived, so I can continue to work on other issues.

[kevmoo]

@srawlins has MANY responsibilities. We just need to be patient.

[chenzhiguang]

Thank you!