Spring Fix function in URI Links section of ref docs

Just fix the same function invoke like this:

URI uri = UriComponentsBuilder
        .fromUriString("https://example.com/hotels/{hotel}?q={q}")
        .build("Westin", "123");

↓

URI uri = UriComponentsBuilder
        .fromUriString("https://example.com/hotels/{hotel}?q={q}")
        .build("Westin", "123")
        .toUri(); // need to create a URI from this instance

Comment From: pivotal-cla

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Comment From: pivotal-cla

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Comment From: sbrannen

Hi @yrucrew,

Thanks for submitting your first pull request to the Spring Framework!

Please note that the org.springframework.web.util.UriComponentsBuilder.build(Object...) method returns a URI.

Thus, the examples you have modified were already correct.

In light of that I am closing this PR.