Add jump label color to horizon-dark theme (#9984)

runtime/themes/horizon-dark.toml

@@ -37,6 +37,7 @@ namespace = "orange"
 "ui.window" = "selection"
 "ui.bufferline" = { bg = "dark-bg", fg = "light-gray" }
 "ui.bufferline.active" = { bg = "dark-bg", fg = "orange" }
+"ui.virtual.jump-label" = { fg = "pink", modifiers = ["bold"] }
 
 # Diagnostics
 "diagnostic" = { underline = { style = "curl" } }