feat: enable zram

modules/nixos/base/misc.nix

@@ -30,6 +30,8 @@
   # Enable in-memory compressed devices and swap space provided by the zram kernel module.
   # By enable this, we can store more data in memory instead of fallback to disk-based swap devices directly, 
   # and thus improve I/O performance when we have a lot of memory.
+  # 
+  #   https://www.kernel.org/doc/Documentation/blockdev/zram.txt
   zramSwap = {
     enable = true;
     # one of "lzo", "lz4", "zstd"