pcsx2: move icon to spec-compliant location

pkgs/by-name/pc/pcsx2/package.nix

@@ -112,7 +112,7 @@ llvmPackages.stdenv.mkDerivation (finalAttrs: {
   strictDeps = true;
 
   postInstall = ''
-    install -Dm644 $src/pcsx2-qt/resources/icons/AppIcon64.png $out/share/pixmaps/PCSX2.png
+    install -Dm644 $src/pcsx2-qt/resources/icons/AppIcon64.png $out/share/icons/hicolor/64x64/apps/PCSX2.png
     install -Dm644 $src/.github/workflows/scripts/linux/pcsx2-qt.desktop $out/share/applications/PCSX2.desktop
 
     zip -jq $out/share/PCSX2/resources/patches.zip ${pcsx2_patches}/patches/*