book: add a line break for code formatting (changkun#224)

lucoiso · web-flow · commit 847b53632de7 · 2022-02-21T10:47:39.000+01:00
diff --git a/book/en-us/02-usability.md b/book/en-us/02-usability.md
@@ -299,7 +299,8 @@ int main() {
     MagicFoo magicFoo = {1, 2, 3, 4, 5};
 
     std::cout << "magicFoo: ";
-    for (std::vector<int>::iterator it = magicFoo.vec.begin(); it != magicFoo.vec.end(); ++it) std::cout << *it << std::endl;
+    for (std::vector<int>::iterator it = magicFoo.vec.begin(); it != magicFoo.vec.end(); ++it) 
+        std::cout << *it << std::endl;
 }
 ```
 

Original file line number	Diff line number	Diff line change
`@@ -299,7 +299,8 @@ int main() {`
`299`	`299`	`MagicFoo magicFoo = {1, 2, 3, 4, 5};`
`300`	`300`
`301`	`301`	`std::cout << "magicFoo: ";`
`302`		`- for (std::vector<int>::iterator it = magicFoo.vec.begin(); it != magicFoo.vec.end(); ++it) std::cout << *it << std::endl;`
	`302`	`+ for (std::vector<int>::iterator it = magicFoo.vec.begin(); it != magicFoo.vec.end(); ++it)`
	`303`	`+ std::cout << *it << std::endl;`
`303`	`304`	`}`
`304`	`305`	```
`305`	`306`