Remove haddock submodule

In preparation for merge into the GHC, as proposed in #23178.

.gitmodules

@@ -91,11 +91,6 @@
 	path = libraries/stm
 	url = https://gitlab.haskell.org/ghc/packages/stm.git
 	ignore = untracked
-[submodule "utils/haddock"]
-	path = utils/haddock
-	url = https://gitlab.haskell.org/ghc/haddock.git
-	ignore = untracked
-	branch = ghc-head
 [submodule "nofib"]
 	path = nofib
 	url = https://gitlab.haskell.org/ghc/nofib.git

packages

@@ -39,7 +39,6 @@
 ghc-tarballs                 windows     ghc-tarballs.git                -
 libffi-tarballs              -           -                               -
 utils/hsc2hs                 -           -                               ssh://git@github.com/haskell/hsc2hs.git
-utils/haddock                -           -                               ssh://git@github.com/haskell/haddock.git
 libraries/array              -           -                               -
 libraries/binary             -           -                               https://github.com/kolmodin/binary.git
 libraries/bytestring         -           -                               https://github.com/haskell/bytestring.git

haddock @ c9bc29c6

-Subproject commit c9bc29c6a708483d2abc3d8ec9262510ce87ca61