fix book example generation and inclusion #537

Job	Run time
Rustfmt	20s
Build Book	8s
Tests (macos-latest)	3m 2s
Clippy	2m 37s
Tests (ubuntu-latest)	2m 9s
semver	1m 59s
Tests (windows-latest)	3m 9s
Code Coverage	26s
Build Examples (3d_charts)	59s
Build Wasm Examples (callback-example)	1m 20s
Build Wasm Examples (basic)	1m 20s
Build Examples (ndarray)	38s
Build Examples (kaleido)	2m 27s
Build Examples (images)	1m 13s
Build Examples (basic_charts)	56s
Build Examples (financial_charts)	58s
Build Examples (custom_controls)	59s
Build Examples (shapes)	25s
Build Examples (scientific_charts)	53s
Build Examples (maps)	37s
Build Examples (subplots)	58s
	27m 33s

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