docs(event handler): fix grammar

[iiio2]

[codecov[bot]]

Codecov Report

All modified and coverable lines are covered by tests :white_check_mark:

Project coverage is 78.76%. Comparing base (a58d7c9) to head (ff9bce0). Report is 173 commits behind head on main.

Additional details and impacted files

```diff @@ Coverage Diff @@ ## main #869 +/- ## ========================================== + Coverage 77.83% 78.76% +0.92% ========================================== Files 47 43 -4 Lines 4286 3291 -995 Branches 611 794 +183 ========================================== - Hits 3336 2592 -744 + Misses 933 696 -237 + Partials 17 3 -14 ```

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[pi0]

Thanks.