Remove the wasm32-wasi target from rustc

This commit is the final step in the journey of renaming the historical
`wasm32-wasi` target in the Rust compiler to `wasm32-wasip1`. Various
steps in this journey so far have been:

* 2023-04-03: rust-lang/compiler-team#607 - initial proposal for this rename
* 2024-11-27: rust-lang/compiler-team#695 - amended schedule/procedure for rename
* 2024-01-29: rust-lang/rust#120468 - initial introduction of `wasm32-wasip1`
* 2024-06-18: rust-lang/rust#126662 - warn on usage of `wasm32-wasi`
* 2024-11-08: this PR - remove the `wasm32-wasi` target

The full transition schedule is in [this comment][comment] and is
summarized with:

* 2024-05-02: Rust 1.78 released with `wasm32-wasip1` target
* 2024-09-05: Rust 1.81 released warning on usage of `wasm32-wasi`
* 2025-01-09: Rust 1.84 to be released without the `wasm32-wasi` target

This means that support on stable for the replacement target of
`wasm32-wasip1` has currently been available for 6 months. Users have
already seen warnings on stable for 2 months about usage of
`wasm32-wasi` and stable users have another 2 months of warnings before
the target is removed from stable.

This commit is intended to be the final step in this transition so the
source tree should no longer mention `wasm32-wasi` except in historical
reference to the older name of the `wasm32-wasip1` target.

[comment]: https://github.com/rust-lang/rust/pull/120468#issuecomment-1977878747

src/doc/rustc/src/platform-support.md

@@ -192,8 +192,8 @@ target | std | notes
 [`thumbv8m.main-none-eabihf`](platform-support/thumbv8m.main-none-eabi.md) | * | Bare Armv8-M Mainline, hardfloat
 [`wasm32-unknown-emscripten`](platform-support/wasm32-unknown-emscripten.md) | ✓ | WebAssembly via Emscripten
 [`wasm32-unknown-unknown`](platform-support/wasm32-unknown-unknown.md) | ✓ | WebAssembly
-`wasm32-wasi` | ✓ | WebAssembly with WASI (undergoing a [rename to `wasm32-wasip1`][wasi-rename])
-[`wasm32-wasip1`](platform-support/wasm32-wasip1.md) | ✓ | WebAssembly with WASI
+[`wasm32-wasip1`](platform-support/wasm32-wasip1.md) | ✓ | WebAssembly with WASIp1
+[`wasm32-wasip2`](platform-support/wasm32-wasip2.md) | ✓ | WebAssembly with WASIp2
 [`wasm32-wasip1-threads`](platform-support/wasm32-wasip1-threads.md) | ✓ | WebAssembly with WASI Preview 1 and threads
 [`wasm32v1-none`](platform-support/wasm32v1-none.md) | * | WebAssembly limited to 1.0 features and no imports
 [`x86_64-apple-ios`](platform-support/apple-ios.md) | ✓ | 64-bit x86 iOS
@@ -377,7 +377,6 @@ target | std | host | notes
 `thumbv7a-pc-windows-msvc` | ✓ |  |
 `thumbv7a-uwp-windows-msvc` | ✓ |  |
 `thumbv7neon-unknown-linux-musleabihf` | ? |  | Thumb2-mode Armv7-A Linux with NEON, musl 1.2.3
-[`wasm32-wasip2`](platform-support/wasm32-wasip2.md) | ✓ |  | WebAssembly
 [`wasm64-unknown-unknown`](platform-support/wasm64-unknown-unknown.md) | ? |  | WebAssembly
 [`x86_64-apple-tvos`](platform-support/apple-tvos.md) | ✓ |  | x86 64-bit tvOS
 [`x86_64-apple-watchos-sim`](platform-support/apple-watchos.md) | ✓ |  | x86 64-bit Apple WatchOS simulator

src/doc/rustc/src/platform-support/wasm32-wasip1.md

@@ -98,10 +98,6 @@ the target with:
 rustup target add wasm32-wasip1
 ```
 
-> **Note**: the `wasm32-wasip1` target is new and may only be available
-> on nightly by the time you're reading this. If `wasm32-wasip1` isn't
-> available on stable Rust then `wasm32-wasi` should be available instead.
-
 Rust programs can be built for that target:
 
 ```text

src/doc/unstable-book/src/compiler-flags/wasm-c-abi.md

@@ -4,7 +4,7 @@ This option controls whether Rust uses the spec-compliant C ABI when compiling
 for the `wasm32-unknown-unknown` target.
 
 This makes it possible to be ABI-compatible with all other spec-compliant Wasm
-like Rusts `wasm32-wasi`.
+like Rusts `wasm32-wasip1`.
 
 This compiler flag is perma-unstable, as it will be enabled by default in the
 future with no option to fall back to the old non-spec-compliant ABI.