[jfx20] RFR: 8290863: Update the documentation of Virtualized controls to include the best practice of not using Nodes directly in the item list [v4]

[Ajit Ghaisas]

> This PR adds a warning about inserting Nodes directly into the virtualized containers such as ListView, TreeView, TableView and TreeTableView. It also adds code snippets showing the recommended pattern of using a custom cell factory for each of the virtualized control.

Ajit Ghaisas has updated the pull request incrementally with one additional commit since the last revision:

  Additional review fixes

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Changes:
  - all: https://git.openjdk.org/jfx/pull/995/files
  - new: https://git.openjdk.org/jfx/pull/995/files/b4335b68..7b441fbf

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jfx&pr=995&range=03
 - incr: https://webrevs.openjdk.org/?repo=jfx&pr=995&range=02-03

  Stats: 25 lines in 5 files changed: 1 ins; 2 del; 22 mod
  Patch: https://git.openjdk.org/jfx/pull/995.diff
  Fetch: git fetch https://git.openjdk.org/jfx pull/995/head:pull/995

PR: https://git.openjdk.org/jfx/pull/995