fix(flake.nix): Fix shellscript

[haruki7049]

This PR fixes the following problem by editing simula-unwrapped in /flake.nix.

The problem

An error occurred on 19edac4, when I run Simula on my device. The reason is that there are no directories for $SIMULA_LOG_DIR, $SIMULA_DATA_DIR and $SIMULA_CONFIG_DIR.

The log when I run Simula on my device:

$ ./result/bin/simula
XDG_CACHE_HOME: /home/haruki/.cache
XDG_DATA_HOME: /home/haruki/.local/share
XDG_CONFIG_HOME: /home/haruki/.config
SIMULA_NIX_DIR: /nix/store/w58nxwwsn97469n480pcw0v4wz833wf2-simula-0.0.0
SIMULA_LOG_DIR: /home/haruki/.cache/Simula
SIMULA_DATA_DIR: /home/haruki/.local/share/Simula
SIMULA_CONFIG_DIR: /home/haruki/.config/Simula
cp: cannot stat '/nix/store/w58nxwwsn97469n480pcw0v4wz833wf2-simula-0.0.0/config/HUD.config': No such file or directory

How to resolve it

• Edited xdgAndSimulaEnvVars in flake.nix to create below directories.
  1. $SIMULA_LOG_DIR
  2. $SIMULA_DATA_DIR
  3. $SIMULA_CONFIG_DIR
• Edited copySimulaConfigFiles in flake.nix to copy correct config/asset files