Use more correct scopes

[tobiasvl]

Some of the scopes we're using now don't fit the current guidelines.

One example is labels. The entire label is entity.name.label, which is good, but the label itself is entity.name.function.label, which is wrong (but which I admit I scoped wrong on purpose, to get a more varied syntax highlighting).

But we should probably be consistent with existing conventions:

• https://manual.macromates.com/en/language_grammars#naming_conventions
• https://www.sublimetext.com/docs/3/scope_naming.html