Break comment to respect 100 column limit (#1069)

CppCoreGuidelines.md

@@ -13399,7 +13399,8 @@ Application concepts are easier to reason about.
 
     void some_fun() {
         std::string  msg, msg2;
-        std::thread publisher([&] { msg = "Hello"; });       // bad (less expressive and more error-prone)
+        std::thread publisher([&] { msg = "Hello"; });       // bad: less expressive
+                                                             //      and more error-prone
         auto pubtask = std::async([&] { msg2 = "Hello"; });  // OK
         // ...
         publisher.join();