users-guide: Remove release notes for 8.2

Bump version to 8.5

The ghc-8.4 branch has now been cut. Updates the haddock submodule.

Release 8.2.2

DynFlags: Introduce -show-mods-loaded flag

This flag reintroduces the verbose module name output produced by GHCi's
:load command behind a new flag, -show-mods-loaded. This was originally
removed in D3651 but apparently some tools (e.g. haskell-mode) rely on
this output.

Addresses #14427.

Test Plan: Validate

Reviewers: svenpanne

Reviewed By: svenpanne

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D4164

(cherry picked from commit 8613e61)

Bump Cabal submodule

includes/rts: Drop trailing comma

This trailing comma snuck in in a recent patch. There is nothing wrong with the
comma; it's perfectly valid C99, yet nevertheless Mac OS X's dtrace utility
chokes on it with,

    dtrace: failed to compile script rts/RtsProbes.d:
            "includes/rts/EventLogFormat.h", line 245: syntax error near "}"
    make[1]: *** [rts/dist/build/RtsProbes.h] Error 1

(cherry picked from commit be514a6)

Release 8.2.1

Bump haddock submodule

base: Fix documentation for forkIOWithUnmask

forkIOUnmasked has been deprecated for several years now. Update reference to
it. See #4858 and #5546.

(cherry picked from commit 1840121)

Revert "Make raiseIO# produce topRes"

This reverts commit da4687f.

It's not entirely trivial to clean up the dead code this patch
introduced. In particular, when we see

```
case raiseIO# m s of
  s' -> e
```

we want to know that `e` is dead. For scrutinees that are properly
bottom (which we don't want to consider `raiseIO# m s` to be, this
is handled by rewriting `bot` to `case bot of {}`. But if we do
that for `raiseIO#`, we end up with

```
case raiseIO# m s of {}
```

which looks a lot like bottom and could confuse demand analysis.
I think we need to wait with this change until we have a more
complete story.

Reviewers: austin, bgamari

Reviewed By: bgamari

Subscribers: rwbarton, thomie

Differential Revision: https://phabricator.haskell.org/D3413

(cherry picked from commit e83af07)