Distinguish PHPDoc annotation arguments clearly

The PHPDoc annotations match the current line greedily. In addition to
this making annotation arguments (e.g. type specifiers) blend in with
the rest of the line it is inconsistent with any continuation lines,
which take the default comment colour. This makes the PHPDoc matching a
little more sophisticated, so annotation arguments and identifiers stand
out.
Merge pull request #19 from commonquail/lazy-annotations

Distinguish PHPDoc annotation arguments clearly