docs: docstring correction

src/OpenSheetMusicDisplay/OSMDOptions.ts

@@ -42,7 +42,7 @@ export interface IOSMDOptions {
     /** Default color for a note head (without stem). Default black (undefined).
      * Only considered before loading a sample, not before render.
      * To change the color after loading a sample and before render, use note(.sourceNote).NoteheadColor.
-     * The format is Vexflow format, either "#rrggbb" or "#rrggbbtt" where <tt> is transparency. All hex values.
+     * The format is Vexflow format, either "#rrggbb" or "#rrggbboo" where <oo> is opacity (00 = transparent). All hex values.
      * E.g., a half-transparent red would be "#FF000080", invisible/transparent would be "#00000000" or "#12345600".
      */
     defaultColorNotehead?: string;