haskell.compiler: drop unnecessary Sphinx patch for GHC >= 9.8

The line the patch touches is actually inside conditional code and isn't
executed with Sphinx 7, so we don't need to touch it.

pkgs/development/compilers/ghc/common-hadrian.nix

@@ -171,11 +171,10 @@
             # 9.8 and 9.10 don't run into this problem for some reason
             || (lib.versionAtLeast version "9.8" && lib.versionOlder version "9.11");
         in
-        [
-          # Fix docs build with Sphinx >= 7 https://gitlab.haskell.org/ghc/ghc/-/issues/24129
-          (if lib.versionAtLeast version "9.8"
-           then ./docs-sphinx-7-ghc98.patch
-           else ./docs-sphinx-7.patch )
+
+        # Fix docs build with Sphinx >= 7 https://gitlab.haskell.org/ghc/ghc/-/issues/24129
+        lib.optionals (lib.versionOlder version "9.8") [
+           ./docs-sphinx-7.patch
         ]
         ++ lib.optionals (lib.versionAtLeast version "9.6" && lib.versionOlder version "9.6.6") [
           (fetchpatch {

pkgs/development/compilers/ghc/docs-sphinx-7-ghc98.patch

@@ -1,8 +0,0 @@
-Fix build of docs after sphinx update.
-https://github.com/sphinx-doc/sphinx/pull/11381
-https://gitlab.haskell.org/ghc/ghc/-/issues/24129
---- a/docs/users_guide/rtd-theme/layout.html
-+++ b/docs/users_guide/rtd-theme/layout.html
-@@ -28 +28 @@
--    <link rel="stylesheet" href="{{ pathto('_static/' + style, 1) }}" type="text/css" />
-+    <link rel="stylesheet" href="{{ pathto('_static/' + styles[-1], 1) }}" type="text/css" />