ChangeLog: Document changes since c83b8c8
ChangeLog: Document changes since c83b8c8

Through f4d221c (Merge pull request #880 from
dqminh/wking-linux-only-capabilities-again, 2017-07-05).  The rc6
release picked up an earlier version of these notes, and those entries
are mostly unchanged except for:

* The credentialSpec entry, which was #814 for credentialspec and now
  also includes #859 for credentialSpec.

* The root(.path) Hyper-V entry, which was #820 for root.path and now
  also includes #838 for root.  I also moved this into the "breaking
  changes" section, because rc5 Hyper-V configs required root to be
  set, and rc6 Hyper-V configs require it to not be set.  Although
  whether rc5 allowed Hyper-V configs at all is not clear to me.

* Fixed indenting for the typo-fixes entry, as well as a number of
  more recent typo-fix PRs.

Signed-off-by: W. Trevor King <f75897670c17327c42ab201733fb8a81ff9f4c34@tremily.us>

hqhq/specs,wking/opencontainer-specs,wking/opencontainer-runtime-spec,laijs/specs,opencontainers/specs,hqhq/runtime-spec,opencontainers/runtime-spec