This change makes Splash merge tokens of the same type (along with any
whitespace in between them) when generating HTML. The result is much
smaller HTML, since less tags have to be used to produce the same result.
This was most obvious with comment highlighting, for example, this comment:
```
// Hello I’m a comment
```
Would generate 5 different <span class="comment"></span> elements. Now
it’s just one!
This change makes it possible to implement custom token types, which is
really useful when building specialized grammars that use non-standard
token types.
This patch makes `HTMLOutputFormat` correctly escape all < and > characters
that occur in source code. Otherwise, a web browser rendering the resulting
HTML will interpret those characters as tags.