Clarify emscripten vs unknown-unknown target usecases

Author: juntyr

src/doc/rustc/src/platform-support/wasm32-unknown-emscripten.md

@@ -5,22 +5,25 @@
 The `wasm32-unknown-emscripten` target is a WebAssembly compilation target which
 uses the [Emscripten](https://emscripten.org/) compiler toolchain. Emscripten is
 a C/C++ toolchain designed to make it as easy as possible to port C/C++ code
-written for Linux to run on the web. It thus provides POSIX-compatible (musl) `libc`
-and `libstd` implementations and many Linux APIs, access to the OpenGL and SDL APIs,
-and the ability to run arbitrary JavaScript code, all based on web APIs using JS
-glue code. With the `wasm32-unknown-emscripten` target, Rust code can interoperate
-with Emscripten's ecosystem, C/C++ and JS code, and web APIs.
+written for Linux to run on the web or in other JavaScript runtimes such as Node.
+It thus provides POSIX-compatible (musl) `libc` and `libstd` implementations and
+many Linux APIs, access to the OpenGL and SDL APIs, and the ability to run arbitrary
+JavaScript code, all based on web APIs using JS glue code. With the
+`wasm32-unknown-emscripten` target, Rust code can interoperate with Emscripten's
+ecosystem, C/C++ and JS code, and web APIs.
 
 One existing user of this target is the
 [`pyodide` project](https://pyodide.org/) which provides a Python runtime in
 WebAssembly using Emscripten and compiles Python extension modules written in Rust
 to the `wasm32-unknown-emscripten` target.
 
-If you want to generate a standalone WebAssembly binary that does not
-require access to the web APIs or the Rust standard library,
-the [`wasm32-unknown-unknown`](./wasm32-unknown-unknown.md) target may be better
-suited for you. However, [`wasm32-unknown-unknown`](./wasm32-unknown-unknown.md) does not (easily)
-support interop with C/C++ code.
+If you want to generate a standalone WebAssembly binary that does not require
+access to the web APIs or the Rust standard library, the
+[`wasm32-unknown-unknown`](./wasm32-unknown-unknown.md) target may be better
+suited for you. However, [`wasm32-unknown-unknown`](./wasm32-unknown-unknown.md)
+does not (easily) support interop with C/C++ code. Please refer to the
+[wasm-bindgen](https://crates.io/crates/wasm-bindgen) crate in case you want to
+interoperate with JavaScript with this target.
 
 Like Emscripten, the WASI targets [`wasm32-wasip1`](./wasm32-wasip1.md) and
 [`wasm32-wasip2`](./wasm32-wasip2.md) also provide access to the host environment,
@@ -118,8 +121,8 @@ To run these tests, both `emcc` and `node` need to be in your `$PATH`. You can
 install `node`, for example, using `nvm` by following the instructions at
 <https://github.com/nvm-sh/nvm#install--update-script>.
 
-Still, it's recommended to test the [`wasm32-wasip1`](./wasm32-wasip1.md) target
-instead for WebAssembly compatibility.
+If you need to test WebAssembly compatibility *in general*, it is recommended
+to test the [`wasm32-wasip1`](./wasm32-wasip1.md) target instead.
 
 ## Conditionally compiling code