treewide: make AppRun substitutions constistent

pkgs/applications/audio/apple-music-electron/default.nix

···
 
     install -m 444 -D ${appimageContents}/${pname}.desktop -t $out/share/applications
     substituteInPlace $out/share/applications/${pname}.desktop \
-      --replace "Exec=AppRun" "Exec=$out/bin/apple-music-electron"
+      --replace 'Exec=AppRun' 'Exec=${pname}'
     cp -r ${appimageContents}/usr/share/icons $out/share
   '';
 

pkgs/applications/audio/nuclear/default.nix

···
 
     install -m 444 -D ${appimageContents}/${pname}.desktop -t $out/share/applications
     substituteInPlace $out/share/applications/${pname}.desktop \
-      --replace 'Exec=AppRun' 'Exec=$out/bin/nuclear'
+      --replace 'Exec=AppRun' 'Exec=${pname}'
     cp -r ${appimageContents}/usr/share/icons $out/share
   '';
 

pkgs/applications/audio/plexamp/default.nix

···
     install -m 444 -D ${appimageContents}/plexamp.desktop $out/share/applications/plexamp.desktop
     install -m 444 -D ${appimageContents}/plexamp.png \
       $out/share/icons/hicolor/512x512/apps/plexamp.png
-    substituteInPlace $out/share/applications/plexamp.desktop \
+    substituteInPlace $out/share/applications/${pname}.desktop \
       --replace 'Exec=AppRun' 'Exec=${pname}'
   '';
 

pkgs/applications/blockchains/crypto-org-wallet.nix

···
     ${imagemagick}/bin/convert ${appimageContents}/${pname}.png -resize 512x512 ${pname}_512.png
     install -m 444 -D ${pname}_512.png $out/share/icons/hicolor/512x512/apps/${pname}.png
     substituteInPlace $out/share/applications/${pname}.desktop \
-      --replace 'Exec=AppRun --no-sandbox %U' "Exec=$out/bin/${pname}"
+      --replace 'Exec=AppRun --no-sandbox %U' 'Exec=${pname} %U'
   '';
 
   meta = with lib; {

pkgs/applications/blockchains/trezor-suite/default.nix

···
     install -m 444 -D ${appimageContents}/${pname}.desktop $out/share/applications/${pname}.desktop
     install -m 444 -D ${appimageContents}/${pname}.png $out/share/icons/hicolor/512x512/apps/${pname}.png
     install -m 444 -D ${appimageContents}/resources/images/icons/512x512.png $out/share/icons/hicolor/512x512/apps/${pname}.png
-    substituteInPlace $out/share/applications/trezor-suite.desktop --replace 'Exec=AppRun' 'Exec=${pname}'
+    substituteInPlace $out/share/applications/${pname}.desktop \
+      --replace 'Exec=AppRun' 'Exec=${pname}'
 
     # symlink system binaries instead bundled ones
     mkdir -p $out/share/${pname}/resources/bin/{bridge,tor}

pkgs/applications/graphics/runwayml/default.nix

···
     postBuild = ''
       mkdir -p $out/share/pixmaps/ $out/share/applications
       cp ${appimage-contents}/usr/share/icons/hicolor/1024x1024/apps/runway.png $out/share/pixmaps/runway.png
-      sed 's:Exec=AppRun:Exec=runwayml:' ${appimage-contents}/runway.desktop > $out/share/applications/runway.desktop
+      substituteInPlace ${appimage-contents}/runway.desktop \
+        --replace 'Exec=AppRun' 'Exec=${pname}'
     '';
 
   meta = with lib; {

pkgs/applications/misc/zettlr/default.nix

···
     mv $out/bin/{${name},${pname}}
     install -m 444 -D ${appimageContents}/Zettlr.desktop $out/share/applications/zettlr.desktop
     install -m 444 -D ${appimageContents}/Zettlr.png $out/share/icons/hicolor/512x512/apps/zettlr.png
-    substituteInPlace $out/share/applications/zettlr.desktop --replace 'Exec=AppRun' 'Exec=${pname}'
+    substituteInPlace $out/share/applications/zettlr.desktop \
+      --replace 'Exec=AppRun' 'Exec=${pname}'
   '';
 
   meta = with lib; {

pkgs/applications/networking/pcloud/default.nix

···
     substitute \
       app/pcloud.desktop \
       share/applications/pcloud.desktop \
-      --replace "Name=pcloud" "Name=pCloud" \
-      --replace "Exec=AppRun" "Exec=$out/bin/pcloud"
+      --replace 'Name=pcloud' 'Name=pCloud' \
+      --replace 'Exec=AppRun' 'Exec=${pname}'
 
     # Build the main executable
     cat > bin/pcloud <<EOF

pkgs/applications/office/timeular/default.nix

···
     mv $out/bin/{${name},${pname}}
     install -m 444 -D ${appimageContents}/timeular.desktop $out/share/applications/timeular.desktop
     install -m 444 -D ${appimageContents}/timeular.png $out/share/icons/hicolor/512x512/apps/timeular.png
-    substituteInPlace $out/share/applications/timeular.desktop --replace 'Exec=AppRun' 'Exec=${pname}'
+    substituteInPlace $out/share/applications/timeular.desktop \
+      --replace 'Exec=AppRun' 'Exec=${pname}'
   '';
 
   meta = with lib; {

pkgs/applications/video/lbry/default.nix

···
     # Now, install assets such as the desktop file and icons
     install -m 444 -D ${src}/lbry.desktop -t $out/share/applications
     substituteInPlace $out/share/applications/lbry.desktop \
-      --replace 'AppRun' '$out/bin/lbry'
+      --replace 'Exec=AppRun' 'Exec=lbry'
     cp -r ${src}/usr/share/icons $out/share
   '';
 

pkgs/tools/misc/betterdiscord-installer/default.nix

···
 
     install -m 444 -D ${appimageContents}/betterdiscord.desktop -t $out/share/applications
     substituteInPlace $out/share/applications/betterdiscord.desktop \
-      --replace "Exec=AppRun" "Exec=$out/bin/${pname}"
+      --replace 'Exec=AppRun' 'Exec=${pname}'
     cp -r ${appimageContents}/usr/share/icons $out/share
   '';