Merge "Improve the docs about when to use introduced." into main am: 04e52144

Original change: https://android-review.googlesource.com/c/platform/build/soong/+/2812358



Change-Id: I251332e390f2dd7044e61ce1924d2c8fc7dbeb0d
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>