Fix copying xcpp.data for xeus-cpp-lite deploy page (#411)

Author: anutosh491

.github/workflows/deploy-pages.yml

@@ -185,7 +185,7 @@ jobs:
           micromamba activate xeus-lite-host
           python -m pip install jupyterlite-xeus
           jupyter lite build --XeusAddon.prefix=${{ env.PREFIX }} --output-dir dist
-          cp xcpp.data dist/extensions/@jupyterlite/xeus/static
+          cp $PREFIX/bin/xcpp.data dist/extensions/@jupyterlite/xeus/static
           cp $PREFIX/lib/libclangCppInterOp.so dist/extensions/@jupyterlite/xeus/static
 
     - name: Upload artifact

Emscripten-build-instructions.md

@@ -155,7 +155,7 @@ we want to include in our application. As of now this would contain all importan
 Libraries etc coming out of emscripten's sysroot. Assuming we are still inside build we should do the following
 
 ```bash
-cp xcpp.data _output/extensions/@jupyterlite/xeus/static
+cp $PREFIX/bin/xcpp.data _output/extensions/@jupyterlite/xeus/static
 cp $PREFIX/lib/libclangCppInterOp.so _output/extensions/@jupyterlite/xeus/static
 ```