Defer scalar conversions

[fktn-k]

In #305, YAML tags are now supported in YAML scalar nodes.
Depending on the tag type, however, unnecessary conversion could occur in the lexer before determining the parsed scalar type based on the given tag.
So, all conversions triggered by the lexer have been changed so that they are defered until the convertion result is actually requested by the deserializer.

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• Changes are described in the pull request or in a referenced issue.
• The test suite compiles and runs without any error.
• The code coverage on your branch is 100%.
• The documentation is updated if you added/changed a feature.

Please don't

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[github-actions]

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Coverage data has been uploaded for the commit b67c07d5b5d6875426b51262e7080157254210cd.
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Name	fkYAML_coverage.pr308.zip
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URL	https://github.com/fktn-k/fkYAML/actions/runs/8666942755/artifacts/1409810930

[coveralls]

Pull Request Test Coverage Report for Build 8666942755

Details

• 300 of 300 (100.0%) changed or added relevant lines in 4 files are covered.
• No unchanged relevant lines lost coverage.
• Overall coverage remained the same at 100.0%

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Totals
Change from base Build 8618687154:	0.0%
Covered Lines:	3452
Relevant Lines:	3452

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