These are unexploded minds as far as the linter is concerned. I don't
want to hit in my MRs by mistake!

I did this with `sed`, and then rolled back some changes in the docs,
config.guess, and the linter itself.

This moves all URL references to Trac Wiki to their corresponding
GitLab counterparts.

This substitution is classified as follows:

1. Automated substitution using sed with Ben's mapping rule [1]
    Old: ghc.haskell.org/trac/ghc/wiki/XxxYyy...
    New: gitlab.haskell.org/ghc/ghc/wikis/xxx-yyy...

2. Manual substitution for URLs containing `#` index
    Old: ghc.haskell.org/trac/ghc/wiki/XxxYyy...#Zzz
    New: gitlab.haskell.org/ghc/ghc/wikis/xxx-yyy...#zzz

3. Manual substitution for strings starting with `Commentary`
    Old: Commentary/XxxYyy...
    New: commentary/xxx-yyy...

See also !539

[1]: https://gitlab.haskell.org/bgamari/gitlab-migration/blob/master/wiki-mapping.json

This adds trace messages that include the processes name and as such
make debugging and following the communication easier.

It also adds a note regarding the fwd*Call proxy-communication logic
between the proxy and the slave.

The proxy will now also poll for 60s to wait for the remote iserv
to come up. (Alternatively you can start the remote process
beforehand; and just have iserv-proxy connect to it)

-Wredundant-record-wildcards warns when a .. pattern binds no variables.

-Wunused-record-wildcards warns when none of the variables bound by a ..
pattern are used.

These flags are enabled by `-Wall`.

Summary:
Currently, the version numbers for `libiserv`, `iserv`, and
`iserv-proxy` are hard-coded directly into their `.cabal` files.
These are easy to forget to update, and in fact, this has already
happened once (see #15866). Let's use `autoconf` to do this for us
so that it is not forgotten in the future.

Test Plan: ./validate

Reviewers: bgamari

Reviewed By: bgamari

Subscribers: rwbarton, erikd, carter

GHC Trac Issues: #15866

Differential Revision: https://phabricator.haskell.org/D5302

Bumps haddock submodule.

Bumps containers submodule, among others.

This reverts commit 50e7bff7514ebbd74976c1a9fa0db7a8275178ae.

Reverts submodule changes.

Sigh, the haskeline commit isn't quite upstream yet.

Bumps containers submodule, among others.