Fix RssHWM -> VmHWM in docs.
Fix RssHWM -> VmHWM in docs.

Change-Id: I8ac40aec8d80a6cb9ff37a172a145b8d3fdf04eb
google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto,google/perfetto