Merge "Fix spacing for preview stabilization mandatory streams docs." into tm-qpr-dev am: 23ac6aceca am: 4bcb7914b8

Original change: https://googleplex-android-review.googlesource.com/c/platform/frameworks/base/+/19572800

Change-Id: Iaf16a291dc42d40257a8a8d872460c66ce3d252b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>