fix(switch): correct value in example

[odsantos]

In the 'switch' article, the code example for grouping cases was using an incorrect value for the variable a. This caused the example to not follow the intended logic of demonstrating the case 4: execution.

This PR corrects the value of a from 3 to 2 + 2, aligning the English version with the corrected Portuguese translation and ensuring the example works as described.