More release notes

Signed-off-by: Austin Seipp <austin@well-typed.com>
Add package flags to --show-options output

Summary: --show-options will now include the package flags.

Test Plan: Pass --show-options to ghc, it should include -package-id.

Reviewers: austin, jstolarek

Subscribers: carter, thomie

Differential Revision: https://phabricator.haskell.org/D554

GHC Trac Issues: #9860
Further improvements to floating equalities

This equality-floating stuff is horribly delicate!  Trac #9316 showed
up yet another corner case.

The main changes are
 * include CTyVarEqs when "growing" the skolem set
 * do not include the kind argument to (~) when growing the skolem set

I added a lot more comments as well

(cherry picked from commit 4b3df0bb705c9287046c07bbc6c038960fbf8d53)
One more documentation note.

Signed-off-by: Austin Seipp <austin@well-typed.com>