Address a comment.

Author: hokein

clang/lib/Sema/SemaCoroutine.cpp

@@ -1748,7 +1748,7 @@ bool CoroutineStmtBuilder::makeOnFallthrough() {
       return false;
   } else if (HasRVoid) {
     Fallthrough = S.BuildCoreturnStmt(FD.getLocation(), nullptr,
-                                      /*IsImplicit*/true);
+                                      /*IsImplicit=*/true);
     Fallthrough = S.ActOnFinishFullStmt(Fallthrough.get());
     if (Fallthrough.isInvalid())
       return false;