Improve Cursor Visibility in Dark Mode

[navneethc]

First up, thanks for adding a dark mode.

But I find that the thickness of the cursor too thin and its retaining the black colour from the light mode makes it very hard to see. Here's a screenshot from Firefox/Windows. (I have DarkReader but it's disabled.)

The visibility seems very slightly better in this image, because the compression has played with the contrast or something, I think. In the actual browser, it's barely visible.

[Deleplace]

cc @jamalc

[zyriab]

Same for the nil new make keywords Maybe that's because I'm colorblind but it's worth a shot :D

EDIT: added other keywords

[navneethc]

Same for the nil keyword Maybe that's because I'm colorblind but it's worth a shot :D

Agree, not easily visible.