doc: remove useless `rec`

doc/languages-frameworks/emscripten.section.md

···
 (pkgs.zlib.override {
   stdenv = pkgs.emscriptenStdenv;
 }).overrideAttrs
-  (old: rec {
+  (old: {
     buildInputs = old.buildInputs ++ [ pkg-config ];
     # we need to reset this setting!
     env = (old.env or { }) // {
···
 This `xmlmirror` example features an Emscripten package that is defined completely from this context and no `pkgs.zlib.override` is used.
 
 ```nix
-pkgs.buildEmscriptenPackage rec {
-  name = "xmlmirror";
+pkgs.buildEmscriptenPackage {
+  pname = "xmlmirror";
+  version = "1.2.3";
 
   buildInputs = [
     pkg-config

doc/packages/emacs.section.md

···
 
 ```nix
 {
-  packageOverrides =
-    pkgs: with pkgs; rec {
-      myEmacsConfig = writeText "default.el" ''
-        (eval-when-compile
-          (require 'use-package))
+  packageOverrides = pkgs: {
+    myEmacsConfig = pkgs.writeText "default.el" ''
+      (eval-when-compile
+        (require 'use-package))
 
-        ;; load some packages
+      ;; load some packages
 
-        (use-package company
-          :bind ("<C-tab>" . company-complete)
-          :diminish company-mode
-          :commands (company-mode global-company-mode)
-          :defer 1
-          :config
-          (global-company-mode))
+      (use-package company
+        :bind ("<C-tab>" . company-complete)
+        :diminish company-mode
+        :commands (company-mode global-company-mode)
+        :defer 1
+        :config
+        (global-company-mode))
 
-        (use-package counsel
-          :commands (counsel-descbinds)
-          :bind (([remap execute-extended-command] . counsel-M-x)
-                 ("C-x C-f" . counsel-find-file)
-                 ("C-c g" . counsel-git)
-                 ("C-c j" . counsel-git-grep)
-                 ("C-c k" . counsel-ag)
-                 ("C-x l" . counsel-locate)
-                 ("M-y" . counsel-yank-pop)))
+      (use-package counsel
+        :commands (counsel-descbinds)
+        :bind (([remap execute-extended-command] . counsel-M-x)
+               ("C-x C-f" . counsel-find-file)
+               ("C-c g" . counsel-git)
+               ("C-c j" . counsel-git-grep)
+               ("C-c k" . counsel-ag)
+               ("C-x l" . counsel-locate)
+               ("M-y" . counsel-yank-pop)))
 
-        (use-package flycheck
-          :defer 2
-          :config (global-flycheck-mode))
+      (use-package flycheck
+        :defer 2
+        :config (global-flycheck-mode))
 
-        (use-package ivy
-          :defer 1
-          :bind (("C-c C-r" . ivy-resume)
-                 ("C-x C-b" . ivy-switch-buffer)
-                 :map ivy-minibuffer-map
-                 ("C-j" . ivy-call))
-          :diminish ivy-mode
-          :commands ivy-mode
-          :config
-          (ivy-mode 1))
+      (use-package ivy
+        :defer 1
+        :bind (("C-c C-r" . ivy-resume)
+               ("C-x C-b" . ivy-switch-buffer)
+               :map ivy-minibuffer-map
+               ("C-j" . ivy-call))
+        :diminish ivy-mode
+        :commands ivy-mode
+        :config
+        (ivy-mode 1))
 
-        (use-package magit
-          :defer
-          :if (executable-find "git")
-          :bind (("C-x g" . magit-status)
-                 ("C-x G" . magit-dispatch-popup))
-          :init
-          (setq magit-completing-read-function 'ivy-completing-read))
+      (use-package magit
+        :defer
+        :if (executable-find "git")
+        :bind (("C-x g" . magit-status)
+               ("C-x G" . magit-dispatch-popup))
+        :init
+        (setq magit-completing-read-function 'ivy-completing-read))
 
-        (use-package projectile
-          :commands projectile-mode
-          :bind-keymap ("C-c p" . projectile-command-map)
-          :defer 5
-          :config
-          (projectile-global-mode))
-      '';
+      (use-package projectile
+        :commands projectile-mode
+        :bind-keymap ("C-c p" . projectile-command-map)
+        :defer 5
+        :config
+        (projectile-global-mode))
+    '';
 
-      myEmacs = emacs.pkgs.withPackages (
-        epkgs:
-        (with epkgs.melpaStablePackages; [
-          (runCommand "default.el" { } ''
-            mkdir -p $out/share/emacs/site-lisp
-            cp ${myEmacsConfig} $out/share/emacs/site-lisp/default.el
-          '')
-          company
-          counsel
-          flycheck
-          ivy
-          magit
-          projectile
-          use-package
-        ])
-      );
-    };
+    myEmacs = emacs.pkgs.withPackages (
+      epkgs:
+      (with epkgs.melpaStablePackages; [
+        (runCommand "default.el" { } ''
+          mkdir -p $out/share/emacs/site-lisp
+          cp ${myEmacsConfig} $out/share/emacs/site-lisp/default.el
+        '')
+        company
+        counsel
+        flycheck
+        ivy
+        magit
+        projectile
+        use-package
+      ])
+    );
+  };
 }
 ```
 

doc/using/configuration.chapter.md

···
 
 ```nix
 {
-  packageOverrides =
-    pkgs: with pkgs; rec {
-      myProfile = writeText "my-profile" ''
-        export PATH=$HOME/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/sbin:/bin:/usr/sbin:/usr/bin
-        export MANPATH=$HOME/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/share/man
-      '';
-      myPackages = pkgs.buildEnv {
-        name = "my-packages";
-        paths = [
-          (runCommand "profile" { } ''
-            mkdir -p $out/etc/profile.d
-            cp ${myProfile} $out/etc/profile.d/my-profile.sh
-          '')
-          aspell
-          bc
-          coreutils
-          ffmpeg
-          man
-          nix
-          emscripten
-          jq
-          nox
-          silver-searcher
-        ];
-        pathsToLink = [
-          "/share/man"
-          "/share/doc"
-          "/bin"
-          "/etc"
-        ];
-        extraOutputsToInstall = [
-          "man"
-          "doc"
-        ];
-      };
+  packageOverrides = pkgs: {
+    myProfile = pkgs.writeText "my-profile" ''
+      export PATH=$HOME/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/sbin:/bin:/usr/sbin:/usr/bin
+      export MANPATH=$HOME/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/share/man
+    '';
+    myPackages = pkgs.buildEnv {
+      name = "my-packages";
+      paths = with pkgs; [
+        (runCommand "profile" { } ''
+          mkdir -p $out/etc/profile.d
+          cp ${myProfile} $out/etc/profile.d/my-profile.sh
+        '')
+        aspell
+        bc
+        coreutils
+        ffmpeg
+        man
+        nix
+        emscripten
+        jq
+        nox
+        silver-searcher
+      ];
+      pathsToLink = [
+        "/share/man"
+        "/share/doc"
+        "/bin"
+        "/etc"
+      ];
+      extraOutputsToInstall = [
+        "man"
+        "doc"
+      ];
     };
+  };
 }
 ```
 
···
 
 ```nix
 {
-  packageOverrides =
-    pkgs: with pkgs; rec {
-      myProfile = writeText "my-profile" ''
-        export PATH=$HOME/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/sbin:/bin:/usr/sbin:/usr/bin
-        export MANPATH=$HOME/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/share/man
-        export INFOPATH=$HOME/.nix-profile/share/info:/nix/var/nix/profiles/default/share/info:/usr/share/info
+  packageOverrides = pkgs: {
+    myProfile = pkgs.writeText "my-profile" ''
+      export PATH=$HOME/.nix-profile/bin:/nix/var/nix/profiles/default/bin:/sbin:/bin:/usr/sbin:/usr/bin
+      export MANPATH=$HOME/.nix-profile/share/man:/nix/var/nix/profiles/default/share/man:/usr/share/man
+      export INFOPATH=$HOME/.nix-profile/share/info:/nix/var/nix/profiles/default/share/info:/usr/share/info
+    '';
+    myPackages = pkgs.buildEnv {
+      name = "my-packages";
+      paths = with pkgs; [
+        (runCommand "profile" { } ''
+          mkdir -p $out/etc/profile.d
+          cp ${myProfile} $out/etc/profile.d/my-profile.sh
+        '')
+        aspell
+        bc
+        coreutils
+        ffmpeg
+        man
+        nix
+        emscripten
+        jq
+        nox
+        silver-searcher
+        texinfoInteractive
+      ];
+      pathsToLink = [
+        "/share/man"
+        "/share/doc"
+        "/share/info"
+        "/bin"
+        "/etc"
+      ];
+      extraOutputsToInstall = [
+        "man"
+        "doc"
+        "info"
+      ];
+      postBuild = ''
+        if [ -x $out/bin/install-info -a -w $out/share/info ]; then
+          shopt -s nullglob
+          for i in $out/share/info/*.info $out/share/info/*.info.gz; do
+              $out/bin/install-info $i $out/share/info/dir
+          done
+        fi
       '';
-      myPackages = pkgs.buildEnv {
-        name = "my-packages";
-        paths = [
-          (runCommand "profile" { } ''
-            mkdir -p $out/etc/profile.d
-            cp ${myProfile} $out/etc/profile.d/my-profile.sh
-          '')
-          aspell
-          bc
-          coreutils
-          ffmpeg
-          man
-          nix
-          emscripten
-          jq
-          nox
-          silver-searcher
-          texinfoInteractive
-        ];
-        pathsToLink = [
-          "/share/man"
-          "/share/doc"
-          "/share/info"
-          "/bin"
-          "/etc"
-        ];
-        extraOutputsToInstall = [
-          "man"
-          "doc"
-          "info"
-        ];
-        postBuild = ''
-          if [ -x $out/bin/install-info -a -w $out/share/info ]; then
-            shopt -s nullglob
-            for i in $out/share/info/*.info $out/share/info/*.info.gz; do
-                $out/bin/install-info $i $out/share/info/dir
-            done
-          fi
-        '';
-      };
     };
+  };
 }
 ```