add --html-pdf-options deprecation warning

index.js

@@ -28,6 +28,7 @@ const args = arg({
 	'--body-class': [String],
 	'--highlight-style': String,
 	'--marked-options': String,
+	'--html-pdf-options': String,
 	'--pdf-options': String,
 	'--md-file-encoding': String,
 	'--stylesheet-encoding': String,
@@ -56,6 +57,15 @@ async function main(args, config) {
 		return 0;
 	}
 
+	if (args['--html-pdf-options']) {
+		console.warn(
+			[
+				chalk.red(`--html-pdf-options is not a valid argument anymore. Use --pdf-options instead.`),
+				chalk.gray(`valid options: https://github.com/GoogleChrome/puppeteer/blob/master/docs/api.md#pagepdfoptions`),
+			].join('\n'),
+		);
+	}
+
 	// markdown file has to be processed first in order to get front-matter config
 	const mdFileContent = readFile(path.resolve(mdFilePath), args['--md-file-encoding'] || config.md_file_encoding);
 	const { content: md, data: frontMatterConfig } = grayMatter(mdFileContent);