RFR: 8325550: Grammatical error in AnchorPane.setLeftAnchor (and other setters) javadoc

[Nir Lisker]

Fixes for the `AnchorPane` docs, as well as for the `NodeOrientation` docs in `Node` and `Scene`.

Note that the default value for a `Scene`'s `NodeOrientation` depends on a system property, while for `Node` it isn't (which means `SubScene` will be different from `Scene`). Not sure if this is intended.

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Commit messages:
 - Initial commit

Changes: https://git.openjdk.org/jfx/pull/1379/files
 Webrev: https://webrevs.openjdk.org/?repo=jfx&pr=1379&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8325550
  Stats: 41 lines in 3 files changed: 4 ins; 6 del; 31 mod
  Patch: https://git.openjdk.org/jfx/pull/1379.diff
  Fetch: git fetch https://git.openjdk.org/jfx.git pull/1379/head:pull/1379

PR: https://git.openjdk.org/jfx/pull/1379