git: openjdk/jdk11u-dev: 8273497: building.md should link to both md and html

[Christoph Langer]

Changeset: 2c47c45f
Author:    Christoph Langer <clanger at openjdk.org>
Date:      2023-02-13 14:19:17 +0000
URL:       https://git.openjdk.org/jdk11u-dev/commit/2c47c45f0747e86a3b97384bea48107627ffd040

8273497: building.md should link to both md and html

Backport-of: a10bb08a4c187c6c0b21cafb25877895d885427e

! doc/building.html
! doc/building.md