finer grain matching for func decl and operators

Small tweaks to the grammar to get an exact match to the Sublime color/syntax highlighting style. Existing styles should not be impacted, and new styles can use support.function.decl, keyword.operator.bracket.go and keyword.operator.punctuation.go.

Punctuation could be expanded to include '...', maybe others.

The names seem wordy, but are consistent w/ the rest of the file.

![image](https://cloud.githubusercontent.com/assets/3619564/4481095/d6b5a700-499c-11e4-9541-f1eaecf8c90f.png)