book: add missing semicolon (changkun#205)

TimothyYe · web-flow · commit 19ceeb7b4f5a · 2021-08-28T21:57:04.000+02:00
diff --git a/book/en-us/02-usability.md b/book/en-us/02-usability.md
@@ -480,7 +480,7 @@ You may think that when we introduce `auto`, we have already mentioned that `aut
 ```cpp
 template<typename R, typename T, typename U>
 R add(T x, U y) {
-    return x+y
+    return x+y;
 }
 ```
 
diff --git a/book/zh-cn/02-usability.md b/book/zh-cn/02-usability.md
@@ -413,7 +413,7 @@ type z == type x
 ```cpp
 template<typename R, typename T, typename U>
 R add(T x, U y) {
-    return x+y
+    return x+y;
 }
 ```
 

Original file line number	Diff line number	Diff line change
@@ -480,7 +480,7 @@ You may think that when we introduce `auto`, we have already mentioned that `aut
`480`	`480`	```cpp
`481`	`481`	`template<typename R, typename T, typename U>`
`482`	`482`	`R add(T x, U y) {`
`483`		`- return x+y`
	`483`	`+ return x+y;`
`484`	`484`	`}`
`485`	`485`	```
`486`	`486`
Original file line number	Diff line number	Diff line change
`@@ -413,7 +413,7 @@ type z == type x`
`413`	`413`	```cpp
`414`	`414`	`template<typename R, typename T, typename U>`
`415`	`415`	`R add(T x, U y) {`
`416`		`- return x+y`
	`416`	`+ return x+y;`
`417`	`417`	`}`
`418`	`418`	```
`419`	`419`