dillon1000/react

Fix grammar typo in Design Principles docs (#9324)

features → feature
> There is nothing "bad" about using state or lifecycle hooks in components. Like any powerful feature**s**, they should be used in moderation, but we have no intention to remove them.

I can’t explain the exact grammatical principle this violates, but it sounds wrong to my native English ears that “feature” is plural here. Another way to check if the grammar sounds right is to change the order of the clauses: ”They should be used in moderation, like any powerful feature“ sounds right, whereas “They should be used in moderation, like any powerful features” does not.