source .env in devshell if one is pressent

.envrc

···
-use flake;
+use flake path:.;
+

shell.nix

···
 {
+  lib,
   mkShell,
   callPackage,
   rustPlatform,
···
 
   env = {
     RUST_SRC_PATH = rustPlatform.rustLibSrc;
-  };
+  }
+  # isabel if this is like a horrible way to do this forgive me for my sins ig
+  # if you can make this better go do it and tell me how or something :3
+  // builtins.fromTOML (
+    (s: if s == "" then s else s + "\"") (lib.replaceStrings [ "\n" "=" "\"" ] [ "\"\n" "=\"" "\\\"" ]
+      (lib.concatStringsSep "\n"
+        (lib.filter (line: !lib.hasPrefix "#" line && line != "")
+          (lib.splitString "\n"
+            (if lib.pathIsRegularFile ./.env
+              then (lib.readFile ./.env)
+              else ""
+            )
+          )
+        )
+      )
+    )
+  );
 
   packages = [
     just