Further canonicalized Android-changed comments

Fixed up two typos and rephrased one occurence of "Android-only",
since the intention of the style guide is for the substring "Android-"
to only occur in documentation for Android changes

After this CL, the only occurences of the substring "Android-"
in ojluni .java files are in lines that contain a match for the
regex pattern

  "Android-(?:changed|added|removed|note)(?:(?:: )?(.*))$"

Test: Treehugger build succeeds
Test: Verified via (unsubmitted) tool that the above statement
      about lines that contain "Android-" holds.
Bug: 35841464

Change-Id: I9903fc50ab2af2b4b16cd317e42aa4dc3b28641a
3 files changed