RFR: 8307409: Refactor usage examples to use @snippet in the java.nio packages

[Brian Burkhalter]

On Mon, 8 May 2023 19:07:25 GMT, Brian Burkhalter <bpb at openjdk.org> wrote:

> Convert the `<pre>{@code ...}</pre>` and some other patterns to `{@snippet ..}`.

It’s unclear whether some of the changes are worthwhile, for example those in `SelectionKey`, or whether others which were **not** made should have been, for example the `<pre>...</pre>` and `<blockquote><pre>...</pre></blockquote>` patterns in `X-Buffer`. Also some changes were made to package private classes which do not appear in the nominal javadoc.

-------------

PR Comment: https://git.openjdk.org/jdk/pull/13870#issuecomment-1538899553