RFR: 8252399: Update mapMulti documentation to use type test pattern instead of instanceof once JEP 375 exits preview [v8]

[Patrick Concannon]

> Hi,
> 
> Could someone please review my changeset for JDK-8252399: 'Update mapMulti documentation to use type test pattern instead of instanceof once JEP 375 exits preview' ?
> 
> This change updates the example code displayed in the API documentation for mapMulti to use the type test pattern introduced in [JEP375](https://openjdk.java.net/jeps/375).
> 
> Kind regards,
> Patrick

Patrick Concannon has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:

 - Merge remote-tracking branch 'origin/master' into JDK-8252399
 - 8252399: Converted JavadocExamples to test
 - Merge remote-tracking branch 'origin/master' into JDK-8252399
 - 825399: Added wildcard to Iterable
 - Merge remote-tracking branch 'origin/master' into JDK-8252399
 - 8252399: Added more appropriate test stream for Expand Iterable example
 - 8252399: Corrected Expand Iterable Example
 - 8252399: Update mapMulti documentation to use type test pattern instead of instanceof once JEP 375 exits preview

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

Changes:
  - all: https://git.openjdk.java.net/jdk/pull/2544/files
  - new: https://git.openjdk.java.net/jdk/pull/2544/files/47dd74df..c47fbf92

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jdk&pr=2544&range=07
 - incr: https://webrevs.openjdk.java.net/?repo=jdk&pr=2544&range=06-07

  Stats: 25663 lines in 916 files changed: 16302 ins; 5038 del; 4323 mod
  Patch: https://git.openjdk.java.net/jdk/pull/2544.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk pull/2544/head:pull/2544

PR: https://git.openjdk.java.net/jdk/pull/2544