Closes #36420
## Synopsis
The issue in #36420 is caused by #7276, which bound the appropriate
tree-sitter queries to the `@variable.member` color. However, I have
found neither this color's declaration nor its other usages in the
codebase (neither on the latest `main` nor on
79c1003b344ee513cf97ee8313c38c7c3f02c916).
Other languages use for such situations the `@property` color.
## Solution
Just change the used `@variable.member` color to the `@property` one.
Seems fully inline with the changes illustrated in #7276.
## Screenshots
<img width="856" height="465" alt="Screenshot 2025-08-28 at 13 18 38"
src="https://github.com/user-attachments/assets/9d1f3542-8749-421f-864f-959c1242cc64"
/>
<img width="837" height="462" alt="Screenshot 2025-08-28 at 13 20 08"
src="https://github.com/user-attachments/assets/36a80c22-9de9-46b1-87e3-7fdeaa62978f"
/>
## Changelog
Release Notes:
- go: Fixed highlighting of fields.