fix: closure error after the compositionend events

[anchengjian]

When I accidentally discovered the error when using contentEditable attr.

[antongorodezkiy]

👍 @anchengjian. Found your PR, when wanted to make my own

Hello @ichord , is there any chance to merge this PR? It's critical issue for triggering events for the element with At.js

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For all other who will need trigger compositionend event on element with At.js for now I can recommend try some other event for triggering popup - click.atwhoInner for example worked for me.