feat(multi): Switch from Vec to impl Accumulate

[epage]

I went with a custom trait so we could cover () and usize as well as
support custom capacities.

This comes at the cost of supporting any container possible. We could
possibly do that with a Extendable(T: Default + Extend) newtype.

As an alternative to () and usize is GATs. The main difference is
who drives the types.

This allowed us to deprecate many[01]_count.

Along the way, we also updated escaped_transform to this so we use this consistently. This exposed why #19 was broken. ExtendInto was implemented both for input and for outputs for the two parsers, which was meant to include char. The backward design of the trait made this less obvious what was happening which I feel is a win for the new trait design.

However, now that Accumulate has no input connection, there isn't quite a proper home for this...

I am conflicted about needing to annotate types when passing a many into something that ignores the output, like recognize. In some respects, I want to require the output type into parsers like recognize to be () but that that will require a lot of void() as that is the minority case. This is a benefit to the GAT approach.

Fixes #122

BREAKING CHANGE: The trait and behavior for escaped_transform changed due to replacing ExtendInto with Accumulate.

[coveralls]

Pull Request Test Coverage Report for Build 4088401767

• 46 of 80 (57.5%) changed or added relevant lines in 4 files are covered.
• 30 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-1.3%) to 57.261%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
src/bytes/complete.rs	3	5	60.0%
src/bytes/streaming.rs	0	4	0.0%
src/multi/mod.rs	23	27	85.19%
src/input.rs	20	44	45.45%

Files with Coverage Reduction	New Missed Lines	%
src/character/complete.rs	2	81.45%
src/multi/mod.rs	28	79.37%

Totals
Change from base Build 4088205250:	-1.3%
Covered Lines:	1668
Relevant Lines:	2913

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💛 - Coveralls