Default decomposition mode in Collator

The description of `Collator.NO_DECOMPOSITION` reads it is the default decomposition mode, but the implementation in Collator's constructor sets the decomposition to `CANONICAL_DECOMPOSITION`. Although the `RuleBasedCollator` which is the sole implementation within the JDK sets the decomposition to `NO_DECOMPOSITION`, It should be up to the implementation of Collator which makes the default, so the description in `NO_DECOMPOSITION` needs to be amended. (Changing the implementation since 1.1 would be too risky)

PoC which returns `CANONICAL_DECOMPOSITION` by default:
```
new RuleBasedCollator("< a< b< c< d").getDecomposition() == Collator.NO_DECOMPOSITION // false
```