2021-October-19 - Prerelease - 2.6.426

Checkstyle Config: remove requirement templated types end in 'T' (#9723)

Templated class types will no longer be required to end in a capital 'T'.

As an example, this update allows the generic type names 'Id' and 'Value'
rather than requiring the names 'IdT' and 'ValueT', EG:

```
public interface TtlCache<Id, Value> {
  Optional<Value> get(Id id);
```

versus before:

```
public interface TtlCache<IdT, ValueT> {
  Optional<ValueT> get(IdT id);
```