use lib.getExe and lib.getExe' in packaged scripts

Replace all ${pkg}/bin/name patterns with:
- lib.getExe pkg (for main executables: curl, jq, gnused, ffmpeg, etc.)
- lib.getExe' pkg "name" (for specific binaries: coreutils, util-linux, etc.)

packages/mushakkil.nix

@@ -1,13 +1,14 @@
 # Add Arabic diacritics (tashkeel) to text via alsharekh.org
 {
+  lib,
   writers,
   curl,
   jq,
 }:
 writers.writeDashBin "mushakkil" ''
-  ${curl}/bin/curl -sSL 'https://diac.alsharekh.org/Diac/DiacText' \
+  ${lib.getExe curl} -sSL 'https://diac.alsharekh.org/Diac/DiacText' \
     -H "Content-Type: application/json" \
-    --data-raw "$(${jq}/bin/jq --raw-input '{word: ., type: 1}')" \
+    --data-raw "$(${lib.getExe jq} --raw-input '{word: ., type: 1}')" \
     --compressed \
-    | ${jq}/bin/jq -r .diacWord
+    | ${lib.getExe jq} -r .diacWord
 ''