Fix typos and annotation use in reference documentation

[yejianfengblue]

1. Change the url in important note to /scanners/search/producers, so as to match the mapping path in @GetMapping(path = "/scanners/search/producers")

2. Change annotation @BasePathAwareController to @RepositoryRestController in the java code examples, because the text is talking about @RepositoryRestController.

3. Change the header @RepositoryRestResource VS. @BasePathAwareController to @RepositoryRestController VS. @BasePathAwareController, because the content is talking about @RepositoryRestController

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[mp911de]

Thank you for your contribution. That's merged, polished, and backported now.