It's more than fair to say in technical documentation you intend others to use having a grammatical error or missing word is confusing and a problem. It's the writing equivalent of having a bug in your code. And it's definitely not "writing to a target audience" as the parent comment suggested. We all make mistakes but don't try to call a mistake effective documentation.
Of course it is, but neither parent nor anyone else is saying anything close to the mistake being effective documentation. There's a single missing word which needs to be added in, but the overall text is clearly writing to a target audience. You are aware of this, and of how small the mistake is, and you understand what the sentence should read as, so I'm not sure what your point is?