Updated SC2113 (markdown)

SC2113.md

@@ -1,16 +1,31 @@
-Instead of 
+## `function` keyword is non-standard. Use `foo()` instead of `function foo`.
 
-``` sh
+### Problematic code:
+
+In `sh`,
+
+```sh
 function quit {
     exit
 }
 ```
 
-...add the parenthesis to the function name and remove the word "function":
+### Correct code:
 
-``` sh
+1. add `()` to after the function name. _this code newly cause [[SC2113]]._
+
+```sh
+function quit() {
+    exit
+}
+#=> SC2112: 'function' keyword is non-standard. Delete it.
+```
+
+2. remove `function`
+
+```sh
 quit() {
     exit
 }
+#=> No issues detected!
 ```
-