Add tealdeer package and configure zsh manpager

- Add tealdeer to the list of packages in default.nix
- Configure zsh to use nvim as the manpager in zsh.nix

home/common/core/default.nix

@@ -29,6 +29,7 @@
       postgresql_16
       libqalculate
       tmux
+      tealdeer
       ;
   };
   home.stateVersion = "24.05";

home/common/core/zsh.nix

@@ -103,6 +103,8 @@
       echo -ne '\e[5 q' # Use beam shape cursor on startup.
       preexec() { echo -ne '\e[5 q' ;} # Use beam shape cursor for each new prompt.
 
+      export MANPAGER="nvim +Man\!"
+
     '';
   };
 }