Merge "Improve the <android/api-level.h> docs slightly." into main am: c5dcd78b97

Original change: https://android-review.googlesource.com/c/platform/bionic/+/3531470

Change-Id: I5e8f39c856a0c1091b8caea98e0baf9306f2090c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>