add anzu emacs package

pkgs/top-level/emacs-packages.nix

@@ -93,6 +93,27 @@ let self = _self // overrides;
     };
   };
 
+  anzu = melpaBuild rec {
+    pname = "anzu";
+    version = "0.52";
+    src = fetchFromGitHub {
+      owner = "syohex";
+      repo  = "emacs-anzu";
+      rev = "f41db6225d8fb983324765aa42c94d3ee379a49f";
+      sha256 = "1mn20swasrl8kr557r1850vr1q0gcnwlxxafnc6lq5g01kjfcdxd";
+    };
+    meta = {
+      description = "Show number of matches in Emacs mode-line while searching";
+      longDescription = ''
+        anzu.el is an Emacs port of anzu.vim. anzu.el provides a minor
+        mode which displays current match and total matches information
+        in the mode-line in various search mode.
+      '';
+      homepage = https://github.com/syohex/emacs-anzu/;
+      license = gpl3Plus;
+    };
+  };
+
   async = melpaBuild rec {
     pname   = "async";
     version = "1.2";