treewide: remove redundant rec

pkgs/shells/dgsh/default.nix

@@ -3,7 +3,7 @@
   perl, texinfo, help2man, gettext, ncurses
 }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation {
   pname = "dgsh-unstable";
   version = "2017-02-05";
 

pkgs/shells/fish/fish-foreign-env/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchFromGitHub, gnused, bash, coreutils }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation {
   pname = "fish-foreign-env";
   version = "git-20170324";
 

pkgs/shells/ksh/default.nix

@@ -1,6 +1,6 @@
 { stdenv, meson, ninja, fetchFromGitHub, which, python, libiconv }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation {
   pname = "ksh";
   version = "93v";
 

pkgs/shells/pash/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchFromGitHub, buildDotnetPackage }:
 
-buildDotnetPackage rec {
+buildDotnetPackage {
   baseName = "pash";
   version = "git-2016-07-06";
   

pkgs/shells/zsh/nix-zsh-completions/default.nix

@@ -4,7 +4,7 @@ let
   version = "0.4.3";
 in
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation {
   pname = "nix-zsh-completions";
   inherit version;
 

pkgs/shells/zsh/spaceship-prompt/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchFromGitHub }:
 
-stdenv.mkDerivation rec{
+stdenv.mkDerivation {
   pname = "spaceship-prompt";
   version = "3.7.1";
 

pkgs/shells/zsh/zsh-command-time/default.nix

@@ -8,7 +8,7 @@
 #     ZSH_COMMAND_TIME_ECHO=1
 #   '';
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation {
   version = "2018-04-30";
   pname = "zsh-command-time";
 

pkgs/shells/zsh/zsh-powerlevel9k/default.nix

@@ -3,7 +3,7 @@
 # To make use of this derivation, use
 # `programs.zsh.promptInit = "source ${pkgs.zsh-powerlevel9k}/share/zsh-powerlevel9k/powerlevel9k.zsh-theme";`
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation {
   pname = "powerlevel9k";
   version = "2017-11-10";
   src = fetchFromGitHub {

pkgs/shells/zsh/zsh-prezto/default.nix

@@ -1,6 +1,6 @@
 { stdenv, fetchgit }:
 
-stdenv.mkDerivation rec {
+stdenv.mkDerivation {
   name = "zsh-prezto-2019-03-18";
   src = fetchgit {
     url = "https://github.com/sorin-ionescu/prezto";