Clean up NPM package and examples (#6589)

This also moves the `demo_gen` code to canonically live in
`tutorials/web-demo` instead of `ffi/capi/bindings` and `ffi/npm`.

Author: robertbastian

ffi/capi/src/segmenter_word.rs

@@ -26,7 +26,7 @@ pub mod ffi {
     /// An ICU4X word-break segmenter, capable of finding word breakpoints in strings.
     #[diplomat::rust_link(icu::segmenter::WordSegmenter, Struct)]
     #[diplomat::rust_link(icu::segmenter::WordSegmenterBorrowed, Struct, hidden)]
-    #[diplomat::demo(custom_func = "../../npm/demo_gen_custom/WordSegmenter.mjs")]
+    #[diplomat::demo(custom_func = "../../../tutorials/web-demo/custom/WordSegmenter.mjs")]
     pub struct WordSegmenter(icu_segmenter::WordSegmenter);
 
     #[diplomat::opaque]

ffi/npm/.gitignore

@@ -1,4 +1,3 @@
 docs
 lib
-demo
 icu_capi.wasm

ffi/npm/.npmignore

@@ -0,0 +1,3 @@
+!lib
+!icu_capi.wasm
+Makefile

ffi/npm/Makefile

@@ -15,10 +15,6 @@ lib/index.mjs: FORCE
 	rm -rf lib
 	cp -r ../capi/bindings/js lib
 
-demo/index.mjs: FORCE
-	rm -rf demo
-	cp -r ../capi/bindings/demo_gen demo
-
 ../../target/wasm32-unknown-unknown/release/icu_capi.wasm: FORCE
 	rustup toolchain install ${PINNED_CI_NIGHTLY}
 	rustup component add rust-src --toolchain ${PINNED_CI_NIGHTLY}
@@ -34,4 +30,4 @@ demo/index.mjs: FORCE
 icu_capi.wasm: ../../target/wasm32-unknown-unknown/release/icu_capi.wasm
 	cp ../../target/wasm32-unknown-unknown/release/icu_capi.wasm icu_capi.wasm
 
-build: lib/index.mjs demo/index.mjs icu_capi.wasm
+build: lib/index.mjs icu_capi.wasm