perf(parse): Remove extra key allocation

[coveralls]

Pull Request Test Coverage Report for Build 10187827492

Details

• 115 of 224 (51.34%) changed or added relevant lines in 14 files are covered.
• 6 unchanged lines in 3 files lost coverage.
• Overall coverage increased (+0.2%) to 67.843%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
crates/toml_edit/src/index.rs	3	4	75.0%
crates/toml_edit/src/parser/inline_table.rs	5	6	83.33%
crates/toml_edit/src/de/table_enum.rs	4	10	40.0%
crates/toml_edit/src/ser/key.rs	3	19	15.79%
crates/toml_edit/src/table.rs	36	70	51.43%
crates/toml_edit/src/inline_table.rs	29	80	36.25%
<!--	Total:	115	224	51.34%	-->

Files with Coverage Reduction	New Missed Lines	%
crates/toml_edit/src/index.rs	1	60.78%
crates/toml_edit/src/item.rs	1	68.1%
crates/toml_edit/src/internal_string.rs	4	29.55%
<!--	Total:	6		-->

Totals
Change from base Build 10185912049:	0.2%
Covered Lines:	3711
Relevant Lines:	5470

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💛 - Coveralls