GraphQL query dark mode - cursor is black when it should be white

[devon-wolf]

When editing a GraphQL query in dark mode, the cursor color is black and very difficult to see. In regular HTTP requests in dark mode the cursor is white.

In this screenshot, the cursor can be (barely) seen on line 5 after the closing curly brace:

I may be able to make a PR for this myself, time permitting, but figured I'd open this issue in the meantime in case I can't get to it. Thank you for such a lovely project!