Increase selection background contrast vs. text

[jmmygoggle]

After importing to my editor, I noticed selected text was difficult to read due to little contrast between the selection background and the selected text.

This change shifts the selection background from an extremely pale blue to a bright but much darker blue so the light color of the selected text is much more visible and readable.

[jesse-c]

@jmmygoggle thank you for the contribution! Since the output was automatically converted from the official theme, it means that if the scripts were re-run, these changes would be lost. I wonder what would be the best way to keep this fix (and probably others).

Some possible solutions:

1. Patch upstream: I don't think this is a reasonable solution, as this is a pretty noticeable issue, and I imagine it's fine in the official theme files.
2. Have some post-conversion fixes applied, like this.

Alternatively, the colours are fine, and it's an issue with the converter.