revert: high contrast Visual

This commit reverts the high contrast Visual highlights in favour of
the previous, neutral behaviour. This allows the foreground highlights
to remain even when selected. Use the previous version in your own
configuration:

```lua
highlight_groups = {
  Visual = { fg = "base", bg = "pine" }
}
```

lua/rose-pine.lua

@@ -83,7 +83,7 @@ local function set_highlights()
 		TabLineSel = { fg = palette.text, bg = palette.overlay, bold = styles.bold },
 		Title = make_title(),
 		VertSplit = make_border(),
-		Visual = { fg = palette.base, bg = palette.pine },
+		Visual = { bg = palette.highlight_med },
 		-- VisualNOS = {},
 		WarningMsg = { fg = groups.warn, bold = styles.bold },
 		-- Whitespace = {},