git: openjdk/jdk-sandbox: classfile-api-dev-branch: fixed building docs

[Adam Sotona]

Changeset: e365c3e4
Author:    Adam Sotona <asotona at openjdk.org>
Date:      2023-03-09 09:00:18 +0000
URL:       https://git.openjdk.org/jdk-sandbox/commit/e365c3e4b8c9ef1f046e39a2db1df383b91d0f14

fixed building docs

! make/Docs.gmk