Spring Docs: Remove duplicate in SpEL feature list

The "relational operators" feature was included twice in the list of SpEL feature list; as part of the "Boolean and relational operators" bullet point and as separate bullet point.

Comment From: pivotal-cla

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Comment From: pivotal-cla

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Comment From: sbrannen

Congratulations on contributing your first PR to the Spring Framework! 👍

This has been merged into main.

Thanks

Comment From: jmewes

Congratulations on contributing your first PR to the Spring Framework! +1

This has been merged into main.

Thanks

Thank you for maintaining the Spring documentation :+1: