Remove outdated contents

Author: kateinoigakukun

src/SUMMARY.md

@@ -18,5 +18,4 @@
     - [Example projects](examples/example-projects.md)
 - [Contribution Guide](contribution-guide/index.md)
     - [How to build the toolchain](contribution-guide/how-to-build-toolchain.md)
-    - [Tips](contribution-guide/tips.md)
 

src/contribution-guide/index.md

@@ -15,26 +15,14 @@ The main repository of this project. Forked from [apple/swift](https://github.co
 
 - `swiftwasm` is the main development branch.
 - `main` is a mirror of the `main` branch of the upstream `apple/swift` repository. This branch is necessary to avoid [some issues](https://github.com/swiftwasm/swift/pull/36).
-- `swiftwasm-release/5.3` is the branch where 5.3 release of SwiftWasm is prepared.
-- `release/5.3` is a mirror of the upstream `release/5.3` branch.
-
-### [swiftwasm/llvm-project](https://github.com/swiftwasm/llvm-project)
-
-This repository is a fork of [apple/llvm-project](https://github.com/apple/llvm-project).
-
-`swiftwasm` branch is based on `swift/main` branch of `apple/llvm-project`.
-
-Please see the [AppleBranchingScheme.md](https://github.com/apple/llvm-project/blob/apple/main/apple-docs/AppleBranchingScheme.md)
-document in the upstream repository for more details.
-
+- `swiftwasm-release/VERSION` is the branch where `VERSION` release of SwiftWasm is prepared.
+- `release/VERSION` is a mirror of the upstream `release/VERSION` branch.
 
 ### [swiftwasm/icu4c-wasi](https://github.com/swiftwasm/icu4c-wasi)
 
 Build script and patches for building ICU project for WebAssembly. [The required changes to build 
 it](https://github.com/unicode-org/icu/pull/990) were merged to the upstream repository.
 
-### [swiftwasm/wasi-sdk](https://github.com/swiftwasm/wasi-sdk) and [swiftwasm/wasi-libc](https://github.com/swiftwasm/wasi-libc)
-
-Forked from [WebAssembly/wasi-sdk](https://github.com/WebAssembly/wasi-sdk) and [WebAssembly/wasi-libc](https://github.com/WebAssembly/wasi-libc).
+### [swiftwasm/wasi-sdk-build](https://github.com/swiftwasm/wasi-sdk-build)
 
-We fork them to build `wasi-sysroot` with pthread header. There aren't so many diff from upstream.
+We apply some patches for [WebAssembly/wasi-sdk](https://github.com/WebAssembly/wasi-sdk) and [WebAssembly/wasi-libc](https://github.com/WebAssembly/wasi-libc) to build `wasi-sysroot` with pthread header. There aren't so many diff from upstream.