Remove `markdown-it` #3454

Job	Run time
Build	5m 19s
Verify build-browser (macos-26)	1m 15s
Print commit stats	1m 3s
Verify build-browser (windows-latest)	1m 49s
Build samples	31s
Verify build-browser (ubuntu-latest)	41s
Static code analysis	4m 0s
Type definitions test	2m 17s
HTML test (1/17)	7m 12s
HTML test (12/17)	7m 33s
HTML test (7/17)	7m 44s
HTML test (13/17)	7m 36s
HTML test (4/17)	7m 39s
HTML test (5/17)	8m 3s
HTML test (11/17)	14m 25s
HTML test (9/17)	8m 27s
Unit test	3m 21s
HTML test (6/17)	7m 57s
HTML test (8/17)	9m 43s
HTML test (17/17)	7m 37s
HTML test (2/17)	7m 33s
HTML test (14/17)	8m 18s
HTML test (16/17)	8m 11s
HTML test (15/17)	10m 49s
HTML test (3/17)	7m 30s
HTML test (10/17)	7m 47s
Merge test results	1m 23s
Merge test snapshots	5s
	2h 45m 48s

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