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

[Adam Sotona]

Changeset: 4f438665
Author:    Adam Sotona <asotona at openjdk.org>
Date:      2022-12-19 10:44:10 +0000
URL:       https://git.openjdk.org/jdk-sandbox/commit/4f438665bf525168042d531b0029820b0156d100

fixed docs building

! make/Docs.gmk