Separate Patterns and Symbols trait methods in DateTimeFormat.

[zbraniecki]

In my journey through a good generic SimpleFormatter, I started looking at the DateTimeFormat and how it handles data.

This is the first step of the clean up, it just separates the trait methods between Symbols and Patterns.

[sffc]

LGTM but please make the CI pass.

[zbraniecki]

I can't. It's bheisler/TinyTemplate#16 so we gotta wait for a new release.

[sffc]

I thought we had a Cargo.lock file so our CI would be more resilient. (You know how I feel about CI breaking because of an external change)

[coveralls]

Pull Request Test Coverage Report for Build 3760a101f41ef0e5f66c546f3b6f0ac04b91dc40-PR-517

• 6 of 12 (50.0%) changed or added relevant lines in 2 files are covered.
• 1 unchanged line in 1 file lost coverage.
• Overall coverage decreased (-0.01%) to 72.696%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
components/datetime/src/format.rs	1	4	25.0%
components/datetime/src/provider/helpers.rs	5	8	62.5%

Files with Coverage Reduction	New Missed Lines	%
components/datetime/src/provider/helpers.rs	1	58.95%

Totals
Change from base Build b15c0b36901095406a67e3620a3d1d0e294b7692:	-0.01%
Covered Lines:	4851
Relevant Lines:	6673

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💛 - Coveralls