Convert tabs to spaces in a couple of rst files

These restructured text files mostly use spaces, but a few stray
tabs crept in.  Change them for consistency.

Change-Id: I89f390d02c737798007423a5126d81ad3d9e032e
Eradicate trailing whitespace

Remove all trailing spaces and tabs in every file in the project.
People have editors configured to do this, which causes them to
accidentally make little whitespace changes in unrelated commits,
which makes those commits harder to review.  Better to fix them all
at once.

Change-Id: I17d89f55f41d8599e0ab1a31f646cd161289703e
Merge "Eradicate trailing whitespace"
Merge "Convert tabs to spaces in a couple of rst files"