RFR: 8357063: Document preconditions for DecimalDigits methods [v3]

[Shaojin Wen]

> Similar to PR #24982 
> Document preconditions on certain DecimalDigits methods that use operations either unsafe and/or without range checks.

Shaojin Wen has updated the pull request incrementally with seven additional commits since the last revision:

 - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
   
   Co-authored-by: Volkan Yazıcı <volkan.yazici at oracle.com>
 - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
   
   Co-authored-by: Volkan Yazıcı <volkan.yazici at oracle.com>
 - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
   
   Co-authored-by: Volkan Yazıcı <volkan.yazici at oracle.com>
 - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
   
   Co-authored-by: Volkan Yazıcı <volkan.yazici at oracle.com>
 - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
   
   Co-authored-by: Volkan Yazıcı <volkan.yazici at oracle.com>
 - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
   
   Co-authored-by: Volkan Yazıcı <volkan.yazici at oracle.com>
 - Update src/java.base/share/classes/jdk/internal/util/DecimalDigits.java
   
   Co-authored-by: Volkan Yazıcı <volkan.yazici at oracle.com>

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

Changes:
  - all: https://git.openjdk.org/jdk/pull/25246/files
  - new: https://git.openjdk.org/jdk/pull/25246/files/ddb44aa8..bcb9af27

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25246&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25246&range=01-02

  Stats: 13 lines in 1 file changed: 0 ins; 8 del; 5 mod
  Patch: https://git.openjdk.org/jdk/pull/25246.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25246/head:pull/25246

PR: https://git.openjdk.org/jdk/pull/25246