remove singlefile's data attribute from stylesheets

Former-commit-id: 8663498591633592e100399b5745dde3fa990a38

lib/single-file/single-file-helper.js

@@ -299,7 +299,7 @@ this.singlefile.lib.helper = this.singlefile.lib.helper || (() => {
 			doc.head.querySelectorAll("*:not(base):not(link):not(meta):not(noscript):not(script):not(style):not(template):not(title)").forEach(element => element.removeAttribute("hidden"));
 		}
 		if (!markedElements) {
-			const singleFileAttributes = [REMOVED_CONTENT_ATTRIBUTE_NAME, PRESERVED_SPACE_ELEMENT_ATTRIBUTE_NAME, IMAGE_ATTRIBUTE_NAME, POSTER_ATTRIBUTE_NAME, CANVAS_ATTRIBUTE_NAME, INPUT_VALUE_ATTRIBUTE_NAME, SHADOW_ROOT_ATTRIBUTE_NAME, HTML_IMPORT_ATTRIBUTE_NAME];
+			const singleFileAttributes = [REMOVED_CONTENT_ATTRIBUTE_NAME, PRESERVED_SPACE_ELEMENT_ATTRIBUTE_NAME, IMAGE_ATTRIBUTE_NAME, POSTER_ATTRIBUTE_NAME, CANVAS_ATTRIBUTE_NAME, INPUT_VALUE_ATTRIBUTE_NAME, SHADOW_ROOT_ATTRIBUTE_NAME, HTML_IMPORT_ATTRIBUTE_NAME, STYLESHEET_ATTRIBUTE_NAME];
 			markedElements = doc.querySelectorAll(singleFileAttributes.map(name => "[" + name + "]").join(","));
 		}
 		markedElements.forEach(element => {
@@ -311,6 +311,7 @@ this.singlefile.lib.helper = this.singlefile.lib.helper || (() => {
 			element.removeAttribute(INPUT_VALUE_ATTRIBUTE_NAME);
 			element.removeAttribute(SHADOW_ROOT_ATTRIBUTE_NAME);
 			element.removeAttribute(HTML_IMPORT_ATTRIBUTE_NAME);
+			element.removeAttribute(STYLESHEET_ATTRIBUTE_NAME);
 		});
 	}