This change enables Splash to highlight multi-line comments that begin
with two asterisks, rather than just one. A test has also been added to
verify that documentation-style multi-line comments with an asterisk on
each line are also highlighted correctly.
This patch fixes syntax highlighting for the following scenario:
```
Type<GenericType>.call()
```
Highlighting generic types is especially tricky, since we want them to
be highlighted when appearing at the call site, like above - but we don’t
want to highlight them when they are being declared. Hopefully with this
fix all/most edge cases are covered.