[Plugin: SyntaxHighlighter Evolved] Gets listed in Google

I’m enjoying this plugin, but just noticed that it gets indexed by google and I’m not exactly the only one.

Check:
https://www.google.nl/search?hl=en&q=/wp-content/plugins/syntaxhighlighter/syntaxhighlighter3/styles/

How can I stop Google (and other searchengines) from stop indexing this plugin, in a proper way?

Thank you in advance!