chore: Remove markdown/highlighting.go and directly use goldmark-highlighting #7977

Job	Run time
setup	6s
Run Main (github-bot) / Go Build / generated	9s
Run Main (github-bot) / Go Lint / lint	27s
Run Main (github-bot) / Go Test / test	35s
Run Main (gnodev) / Go Lint / lint	47s
Run Main (gnodev) / Go Build / generated	14s
Run Main (gnodev) / Go Test / test	1m 18s
Run Main (gnofaucet) / Go Test / test	41s
Run Main (gnofaucet) / Go Lint / lint	38s
Run Main (gnofaucet) / Go Build / generated	8s
Run Main (gnogenesis) / Go Build / generated	12s
Run Main (gnogenesis) / Go Lint / lint	47s
Run Main (gnogenesis) / Go Test / test	42s
Run Main (gnohealth) / Go Build / generated	13s
Run Main (gnohealth) / Go Lint / lint	31s
Run Main (gnohealth) / Go Test / test	37s
Run Main (gnokeykc) / Go Build / generated	6s
Run Main (gnokeykc) / Go Test / test	45s
Run Main (gnokeykc) / Go Lint / lint	38s
Run Main (gnomd) / Go Build / generated	11s
Run Main (gnomd) / Go Test / test	34s
Run Main (gnomd) / Go Lint / lint	29s
Run Main (gnomigrate) / Go Build / generated	11s
Run Main (gnomigrate) / Go Lint / lint	36s
Run Main (gnomigrate) / Go Test / test	45s
	12m 20s

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