home: several changes

- add TEXMFHOME variable
- Include mutable_config to ssh config
- add package `kondo`
- mpd uses xdg music userdir

home/programs/git.nix

@@ -1,4 +1,4 @@
-{pkgs, ...}:
+{ pkgs, ... }:
 {
   programs.git = {
     enable = true;
@@ -12,6 +12,15 @@
       signByDefault = true;
     };
 
+    delta = {
+      enable = true;
+      options = {
+        line-numbers = true;
+        side-by-side = true;
+        theme = "Monokai Extended Origin";
+      };
+    };
+
     aliases = {
         aliases = "!git config --get-regexp alias | sed -re 's/alias\\.(\\S*)\\s(.*)$/\\1 = \\2/g'";
         uncommit = "reset --soft HEAD^";
@@ -39,7 +48,6 @@
         untrackedCache = true;
 
         editor = "nvim";
-        pager = "less";
       };
 
       "color \"branch\"".upstream = "cyan";