Fix a typo

tatsuya6502 · tatsuya6502 · commit 19fbab9878e1 · 2019-07-04T10:09:49.000+08:00
diff --git a/src/atcoder-env/compiling-and-running-program.md b/src/atcoder-env/compiling-and-running-program.md
@@ -170,7 +170,7 @@ $ ./test_jemallocator
 ...
 
 ## こちらも終了コード0で終了したことだけを確認すればOK
-$ $?
+$ echo $?
 0
 ```
 

Original file line number	Diff line number	Diff line change
`@@ -170,7 +170,7 @@ $ ./test_jemallocator`
`170`	`170`	`...`
`171`	`171`
`172`	`172`	`## こちらも終了コード0で終了したことだけを確認すればOK`
`173`		`-$ $?`
	`173`	`+$ echo $?`
`174`	`174`	`0`
`175`	`175`	```
`176`	`176`