Blender Git Loki

Fix T61253: Wrong syntax highlighting when @ is used as multiplication

This is obviously not a perfect solution. However, to do proper
highlighting a more advanced Python parser would be necessary.
I think this patch implements a good heuristic to differentiate
between the cases when `@` is used for a decorator vs for
multiplication.

When `@` is directly followed by an identifier, it is interpreted
as decorated. Otherwise not.

Reviewers: brecht

Differential Revision: https://developer.blender.org/D4495