blade: fix path rasterization (#7546)

There were mistakes in the blending mode, primitive topology, and the
equation.

![gpui-text-selection](https://github.com/zed-industries/zed/assets/107301/13f1285e-1338-4c87-b1bb-7e426606f939)



Release Notes:
- N/A
d457eef099Dzmitry Malyshau committed on 2/8/2024, 2:08:04 PM· committed by GitHubparent00024b7
2 files changedLine totals unavailable