Updated README with a couple of links to SwiftSyntax clients

Added `swift-format` and `SwiftSemantics`

Author: akyrtzi

README.md

@@ -82,8 +82,12 @@ the Swift compiler source because we always push gyb-generated files to a tag.
 
 [**Swift AST Explorer**](https://swift-ast-explorer.kishikawakatsumi.com/): a Swift AST visualizer.
 
+[**swift-format**](https://github.com/apple/swift-format): formatting technology for Swift source code.
+
 [**Swift Stress Tester**](https://github.com/apple/swift-stress-tester): a test driver for sourcekitd and Swift evolution.
 
+[**SwiftSemantics**](https://github.com/SwiftDocOrg/SwiftSemantics): parses Swift code into its constituent declarations.
+
 [**SwiftRewriter**](https://github.com/inamiy/SwiftRewriter): a Swift code formatter.
 
 [**SwiftPack**](https://github.com/omochi/SwiftPack): a tool for automatically embedding Swift library source.