Add example values to .d.ts

typings/xterm.d.ts

@@ -151,8 +151,12 @@ declare module 'xterm' {
     /**
      * The minimum contrast ratio for text in the terminal, setting this will
      * change the foreground color dynamically depending on whether the contrast
-     * ratio is met. This can be to set 0.1 increments between 1 (default, do
-     * nothing) and 21 (foreground will be black or white).
+     * ratio is met. Example values:
+     *
+     * - 1: The default, do nothing.
+     * - 4.5: Minimum for WCAG AA compliance.
+     * - 7: Minimum for WCAG AAA compliance.
+     * - 21: White on black or black on white.
      */
     minimumContrastRatio?: number;