Wipe cache when HID report cache isn't compatible with the current cache version.

This is to fix a big triggered by the OTA from any previous version to S
due to the structure change of the cache report entries.

Also corrected minor typos in documentation.

Tag: #stability
Test: Bond with HID device, upgrade from Q to S, verify device is
working.
Bug: 178874105
Bug: 159868059

Change-Id: Ibbd5da90892a637ffe8ff09b2b98bfc9fe3fb0cd