Only aware of the numeric versions of some entities

https://www.compart.com/en/unicode/U+2588 says this character is \&block;

Alas,
```
$ echo █|perl -C -MHTML::Entities -nwle 'print encode_entities $_;'
&#x2588;
```
the module is only aware of the numeric version.

Package: libhtml-parser-perl             
Version: 3.83-1