ref(extend-app-start): Drop redundant javadoc on IAppStartExtender methods

The class javadoc already enumerates the Sentry.* methods; the per-method
javadoc just restated the method names.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: buenaflor

sentry/src/main/java/io/sentry/IAppStartExtender.java

@@ -12,15 +12,13 @@
 @ApiStatus.Internal
 public interface IAppStartExtender {
 
-  /** Starts extending the app start measurement. See {@code Sentry.extendAppStart()}. */
   void extendAppStart();
 
-  /** Finishes the extended app start. See {@code Sentry.finishAppStart()}. */
   void finishAppStart();
 
   /**
    * Returns the active extended app start span to attach child spans to, or a no-op span when no
-   * extension is active. See {@code Sentry.getExtendedAppStartSpan()}.
+   * extension is active.
    */
   @NotNull
   ISpan getExtendedAppStartSpan();