Add heredoc delimiter documentation on hover #10600

Job	Run time
build_node (ubuntu-latest)	1m 5s
build_node (macos-latest)	1m 56s
build_node (windows-latest)	7m 4s
Ruby 3.1 on ubuntu-latest	12m 25s
Ruby 3.2 on ubuntu-latest	12m 9s
lint_node	26s
Ruby 3.3 on ubuntu-latest	11m 19s
Ruby 3.1 on macos-latest	8m 36s
Ruby 3.2 on macos-latest	7m 40s
lint_ruby	24s
Ruby 3.3 on macos-latest	5m 36s
Ruby 3.1 on windows-latest	18m 34s
Ruby 3.2 on windows-latest	17m 32s
Ruby 3.3 on windows-latest	18m 52s
Verify Jekyll website builds	12s
	2h 3m 50s

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