Exposed colors sample update in the playground.

test/playground.generated/customizing-the-appearence-exposed-colors.html

@@ -141,6 +141,7 @@ monaco.editor.create(document.getElementById("container"), {
 'editorWhitespace.foreground' // Color of whitespace characters in the editor.
 'editorIndentGuide.background' // Color of the editor indentation guides.
 'editorLineNumber.foreground' // Color of editor line numbers.
+'editorLineNumber.activeForeground' // Color of editor active line number.
 'editorRuler.foreground' // Color of the editor rulers.
 'editorCodeLens.foreground' // Foreground color of editor code lenses
 'editorBracketMatch.background' // Background color behind matching brackets

website/playground/new-samples/customizing-the-appearence/exposed-colors/sample.js

@@ -104,6 +104,7 @@ monaco.editor.create(document.getElementById("container"), {
 'editorWhitespace.foreground' // Color of whitespace characters in the editor.
 'editorIndentGuide.background' // Color of the editor indentation guides.
 'editorLineNumber.foreground' // Color of editor line numbers.
+'editorLineNumber.activeForeground' // Color of editor active line number.
 'editorRuler.foreground' // Color of the editor rulers.
 'editorCodeLens.foreground' // Foreground color of editor code lenses
 'editorBracketMatch.background' // Background color behind matching brackets