Update nord.toml (#10307)

When "nord2" color is used in ui.selection it is almost invisible
if cursorline highlighting is enabled. Changing the color to "nord3" fixes the issue.

runtime/themes/nord.toml

@@ -114,7 +114,7 @@
 "ui.cursorcolumn.primary" = { bg = "nord1" }
 "ui.cursorline.primary" = { bg = "nord1" }
 
-"ui.selection" = { bg = "nord2" }
+"ui.selection" = { bg = "nord3" }
 "ui.highlight" = { fg = "nord8", bg = "nord2" }
 
 # Statusline