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fix(docs): copy section permalinks and polish outline navigation #2126

Job	Run time
docs changes	32s
docs benchmark (${{ matrix.target }})	0s
docs build	2m 23s
docs source	3m 28s
docs acceptance (webkit)	2m 5s
docs acceptance (chromium)	2m 9s
docs acceptance (http)	1m 56s
docs acceptance (corpus)	2m 38s
docs HTTP	3s
	15m 14s