fix(css): handle trailing line comments in embedded styles (#120)

Author: TRIS-H

packages/css/index.ts

@@ -289,10 +289,12 @@ export function create({
 						let suffixes = [];
 
 						if (codeOptions?.initialIndentLevel) {
+							const documentText = document.getText();
+							const lastSuffix = endWithNewLine(documentText) ? '}' : '\n}';
 							for (let i = 0; i < codeOptions.initialIndentLevel; i++) {
 								if (i === codeOptions.initialIndentLevel - 1) {
 									prefixes.push('_', '{');
-									suffixes.unshift('}');
+									suffixes.unshift(lastSuffix);
 								}
 								else {
 									prefixes.push('_', '{\n');
@@ -303,7 +305,7 @@ export function create({
 								document.uri,
 								document.languageId,
 								document.version,
-								prefixes.join('') + document.getText() + suffixes.join(''),
+								prefixes.join('') + documentText + suffixes.join(''),
 							);
 							formatRange = {
 								start: formatDocument.positionAt(0),
@@ -336,11 +338,12 @@ export function create({
 						return edits;
 
 						function ensureNewLines(newText: string) {
+							const verifySuffix = endWithNewLine(newText) ? '}' : '\n}';
 							const verifyDocument = TextDocument.create(
 								document.uri,
 								document.languageId,
 								document.version,
-								'_ {' + newText + '}',
+								'_ {' + newText + verifySuffix,
 							);
 							const verifyEdits = cssLs.format(verifyDocument, undefined, formatOptions);
 							let verifyText = TextDocument.applyEdits(verifyDocument, verifyEdits);