Merge pull request #1229 from GaoZG2/patch-2

Update string-slice.md

src/basic/compound-type/string-slice.md

@@ -600,6 +600,7 @@ fn main() {
     );
 
     // 换行了也会保持之前的字符串格式
+    // 使用\忽略换行符
     let long_string = "String literals
                         can span multiple lines.
                         The linebreak and indentation here ->\