Use proper namespace for 'class' instead of custom detection logic.

[vovayatsyuk]

A bunch of code was removed and replaced with proper scope name.

p.s. This code came to this project from uikit-sublime. It was added by uikit-sublime plugin developer because that module allows inserting a snippet not only inside a class scope but directly into a tag: https://github.com/uikit/uikit-sublime/blob/master/main.py#L11-L12

This plugin doesn't have this feature, so we could remove it completely.