Update Suffix.md

[CheATSlark]

Description
Fixed code formatting in example code by adding missing closing parenthesis.

Rationale
The code example in line 12 of Suffix.md was missing a closing parenthesis. This change ensures the example code is correctly formatted and syntactically valid.

Checklist

• I've added at least one test that validates that my change is working, if appropriate
• I've followed the code style of the rest of the project
• I've read the Contribution Guidelines
• I've updated the documentation if necessary

[CheATSlark]

@swift-ci please test

[glessard]

@swift-ci please test

[glessard]

Thanks @CheATSlark