RFR: 8233749: Files.exists javadoc doesn't mention eating IOException

[Brian Burkhalter]

Add `@see FileSystemProvider#checkAccess` link per the suggestion in the issue.

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Commit messages:
 - 8233749: Files.exists javadoc doesn't mention eating IOException

Changes: https://git.openjdk.java.net/jdk/pull/5856/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk&pr=5856&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8233749
  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk/pull/5856.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/5856/head:pull/5856

PR: https://git.openjdk.java.net/jdk/pull/5856