i18n(ko-KR): update `fontmatter.md` #7112

Job	Run time
changes	4s
Check for accessibility issues	2m 8s
Run type checks	31s
Docs site builds on Windows	1m 34s
Check for broken links	1m 1s
Run E2E tests (${{ matrix.os }})	0s
Run unit tests	0s
	5m 18s

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