Update README with new links

Signed-off-by: Keith Smiley <[email protected]>

README.md

@@ -18,7 +18,7 @@ Path remapping is done with regex substitution. `index-import` accepts one or mo
 
 ### Index File Format
 
-The index consists of two types of files, Unit files and Record files. Both are [LLVM Bitstream](https://www.llvm.org/docs/BitCodeFormat.html#bitstream-format), a common binary format used by LLVM/Clang/Swift. Record files contain no paths and can be simply copied. Only Unit files contain paths, so only unit files need to be rewritten. A read/write API is available in the `clangIndex` library. `index-import` uses [`IndexUnitReader`](https://github.com/apple/swift-clang/blob/swift-5.0-branch/include/clang/Index/IndexUnitReader.h) and [`IndexUnitWriter`](https://github.com/apple/swift-clang/blob/swift-5.0-branch/include/clang/Index/IndexUnitWriter.h).
+The index consists of two types of files, Unit files and Record files. Both are [LLVM Bitstream](https://www.llvm.org/docs/BitCodeFormat.html#bitstream-format), a common binary format used by LLVM/Clang/Swift. Record files contain no paths and can be simply copied. Only Unit files contain paths, so only unit files need to be rewritten. A read/write API is available in the `clangIndex` library. `index-import` uses [`IndexUnitReader`](https://github.com/apple/llvm-project/blob/swift/release/5.5/clang/include/clang/Index/IndexUnitReader.h) and [`IndexUnitWriter`](https://github.com/apple/llvm-project/blob/swift/release/5.5/clang/include/clang/Index/IndexUnitWriter.h).
 
 ## Resources
 
@@ -44,7 +44,7 @@ index-import \
     "$build_dir2/Index/DataStore"
 ```
 
-A more complex example is importing an index from a [Bazel](https://bazel.build) built project. This example makes would be run as an Xcode "Run Script" build phase, which provides many environment variables, including: `SRCROOT`, `CONFIGURATION_TEMP_DIR`, `ARCHS`.
+A more complex example is importing an index from a [Bazel](https://bazel.build) built project. This example would be run as an Xcode "Run Script" build phase, which provides many environment variables, including: `SRCROOT`, `CONFIGURATION_TEMP_DIR`, `ARCHS`.
 
 ```sh
 #!/bin/bash
@@ -75,15 +75,13 @@ index-import \
 
 ## Build Instructions
 
-The build uses [CMake](https://cmake.org) because [swift-clang](https://www.github.com/apple/swift-clang) uses CMake. The `index-import` build script is small, but depends on the larger swift-clang project. To build `index-import`, first [install the tools required by Swift](https://github.com/apple/swift/blob/main/docs/HowToGuides/GettingStarted.md#system-requirements), then build swift-clang by following the [Swift build instructions](https://github.com/apple/swift/blob/main/docs/HowToGuides/GettingStarted.md#building-the-project-for-the-first-time).
+The build uses [CMake](https://cmake.org) because [Apple's LLVM fork](https://github.com/apple/llvm-project) uses CMake. The `index-import` build script is small, but depends on the libraries from LLVM. To build `index-import`, first [install the tools required by Swift](https://github.com/apple/swift/blob/main/docs/HowToGuides/GettingStarted.md#system-requirements), then build swift by following the [Swift build instructions](https://github.com/apple/swift/blob/main/docs/HowToGuides/GettingStarted.md#building-the-project-for-the-first-time).
 
 When building Swift, keep the following in mind:
 
-1. Checkout the desired release branch of Swift
+1. Checkout the desired release branch of Swift using something like `./swift/utils/update-checkout --clone --scheme release/5.5`.
 2. Build Swift using `--release`/`-R` for performance
 
-To checkout a specific version of Swift, use the `update-checkout` script. For example: `./swift/utils/update-checkout --clone --tag swift-5.0.1-RELEASE`.
-
 Building all of Swift can take a long time, and most of that isn't needed by `index-import`. A faster way to build `index-import`, is to build only `libIndexStore.dylib`. Here are the commands to do just that:
 
 ```sh