Update javascript-procedural-proto.md (cyberbotics#6290)

Author: omichel

docs/reference/javascript-procedural-proto.md

@@ -157,7 +157,7 @@ A number of modules provide additional utility functions that can be useful when
 To use these functions, the module needs to be included first:
 
 ```javascript
-%{
+%<
   // to import the entire module
   import * as wbrandom from 'wbrandom.js';
 
@@ -166,7 +166,7 @@ To use these functions, the module needs to be included first:
 
   // to import only specific functions instead of the entire module
   import {integer} from 'wbrandom.js';
-}%
+>%
 ```
 
 The available modules are the following: