Doc change on java.text.BreakIterator

- Since BreakIterator wraps its ICU4J peer, but the doc doesn't
  mention any linkage to ICU4J, specify the behavior of ICU4J to
  discourage modification on CharacterIterator after setText

Bug: 80456574
Test: m docs
Merged-In: If2564ca99911a1bb1470d80934f250b227fdf3b3
Change-Id: If2564ca99911a1bb1470d80934f250b227fdf3b3
(cherry picked from commit 22660b8dd20227ad8f0d5bcaf7717b48793fb10d)
1 file changed