Fix OS singleton being incorrectly highlighted as a constant

[DaelonSuzuka]

[Calinou]

OS is not a primitive type like int or Vector2, so it shouldn't be highlighted this way. The issue is likely elsewhere.

How does the highlighting of other singletons like Engine or VisualServer look?

[DaelonSuzuka]

All the other built-in singletons are PascalCase so they're green like classes.

[Calinou]

My guess is that the const highlight is kicking in as the identifier's name is all-uppercase. (The built-in script editor doesn't have such a highlight, but maybe this extension does.)

[DaelonSuzuka]

Yeah, that's exactly what's happening. OS doesn't trigger the same rule as the other singletons because it doesn't have any lower case letters. This change is just bringing OS in line with the other singletons.

[Calinou]

Thanks!