Update documentation for "Lightweight mode" am: 1332f5e780
Update documentation for "Lightweight mode" am: 1332f5e780

Original change: https://android-review.googlesource.com/c/platform/external/perfetto/+/1874015

Change-Id: I426e301341fa24a9cda94a95788f24271d1a3206

google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto