treewide: simplify rev/repo arguments in src

+ use fetchFromGithub where possible

pkgs/tools/misc/ddate/default.nix

@@ -1,10 +1,13 @@
-{stdenv, fetchgit, cmake} :
+{stdenv, fetchFromGitHub, cmake} :
 
-stdenv.mkDerivation {
-  name = "ddate-0.2.2";
-  src = fetchgit {
-    url = "https://github.com/bo0ts/ddate";
-    rev = "refs/tags/v0.2.2";
+stdenv.mkDerivation rec {
+  pname = "ddate";
+  version = "0.2.2";
+
+  src = fetchFromGitHub {
+    owner = "bo0ts";
+    repo = pname;
+    rev = "refs/tags/v${version}";
     sha256 = "1qchxnxvghbma6gp1g78wnjxsri0b72ha9axyk31cplssl7yn73f";
   };
 
@@ -14,7 +17,7 @@ stdenv.mkDerivation {
     homepage = "https://github.com/bo0ts/ddate";
     description = "Discordian version of the date program";
     license = stdenv.lib.licenses.publicDomain;
-    maintainers = with stdenv.lib.maintainers; [kovirobi];
+    maintainers = with stdenv.lib.maintainers; [ kovirobi ];
     platforms = stdenv.lib.platforms.all;
   };
 }