OPENNLP-1007: Fix typo in evaluation monitor method signature

[mawiesne]

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[mawiesne]

@kinow It's now reduced to a single commit.

[kinow]

Thank you @mawiesne ! Because it is a change in the public API, I will let @jzonthemtn do the final review & merge here 👍 But it looks good to me. Thanks!

[jzonthemtn]

I'm good with it. Spelling is important! :)