alacritty-theme: don't litter / (#373314)

pkgs/by-name/al/alacritty-theme/package.nix

···
   sourceRoot = "${self.src.name}/themes";
   installPhase = ''
     runHook preInstall
-    install -Dt $out *.toml
+    install -Dt $out/share/alacritty-theme *.toml
     runHook postInstall
   '';