Finish converting all events to jspecify annotations

patches/api/Add-PrepareResultEvent-PrepareGrindstoneEvent.patch

@@ -79,6 +79,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     *
 +     * @return result item
 +     */
++    @Override
 +    public @Nullable ItemStack getResult() {
 +        return super.getResult();
 +    }
@@ -88,6 +89,7 @@ index 0000000000000000000000000000000000000000..00000000000000000000000000000000
 +     *
 +     * @param result result item
 +     */
++    @Override
 +    public void setResult(final @Nullable ItemStack result) {
 +        super.setResult(result);
 +    }