RFR: 8364146: JList getScrollableUnitIncrement return 0 [v4]

[Prasanta Sadhukhan]

> It seems JList.getScrollableUnitIncrement can sometime return 0 instead of positive number which is not specified in the javadoc which can lead to confusion. Clarified javadoc as to when it can return 0.

Prasanta Sadhukhan has updated the pull request incrementally with one additional commit since the last revision:

  Restrict negative increment

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/26500/files
  - new: https://git.openjdk.org/jdk/pull/26500/files/b4d22ac9..ba88e12e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=26500&range=03
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=26500&range=02-03

  Stats: 2 lines in 1 file changed: 1 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/26500.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/26500/head:pull/26500

PR: https://git.openjdk.org/jdk/pull/26500