treewide: run treefmt with mdcr/nixfmt

doc/languages-frameworks/haskell.section.md

@@ -783,9 +783,7 @@ need to build `nix-tree` with a more recent version of `brick` than the default
 one provided by `haskellPackages`:
 
 ```nix
-haskellPackages.nix-tree.override {
-  brick = haskellPackages.brick_0_67;
-}
+haskellPackages.nix-tree.override { brick = haskellPackages.brick_0_67; }
 ```
 
 <!-- TODO(@sternenseemann): This belongs in the next section
@@ -841,8 +839,8 @@ let
       install -Dm644 man/${drv.pname}.1 -t "$out/share/man/man1"
     '';
   });
-in
 
+in
 installManPage haskellPackages.pnbackup
 ```
 
@@ -1310,8 +1308,8 @@ let
   ghcName = "ghc92";
   # Desired new setting
   enableProfiling = true;
-in
 
+in
 [
   # The first overlay modifies the GHC derivation so that it does or does not
   # build profiling versions of the core libraries bundled with it. It is
@@ -1322,8 +1320,8 @@ in
     final: prev:
     let
       inherit (final) lib;
-    in
 
+    in
     {
       haskell = prev.haskell // {
         compiler = prev.haskell.compiler // {
@@ -1341,8 +1339,8 @@ in
     let
       inherit (final) lib;
       haskellLib = final.haskell.lib.compose;
-    in
 
+    in
     {
       haskell = prev.haskell // {
         packages = prev.haskell.packages // {