Update ChangingSwiftSyntax.md

Update some outdated comments from ChangingSwiftSyntax.md

Author: ahoppen

Sources/SwiftSyntax/Documentation.docc/Contributing/ChangingSwiftSyntax.md

@@ -12,31 +12,27 @@ structures in sync, this project generates code using the Swift package
 ## Regenerating Files
 
 To re-generate the files after changing `CodeGeneration` run the `generate-swiftsyntax` 
-target of `CodeGeneration` and pass `path/to/swift-syntax/Sources` as the argument.
+target of `CodeGeneration`.
 
 On the command line, this would be
 ```bash
-swift run --package-path CodeGeneration generate-swiftsyntax Sources
+swift run --package-path CodeGeneration generate-swiftsyntax
 ```
 
-Or if you open the `CodeGeneration` package in Xcode, you can add the 
-`generate-swift syntax ../Sources` arguments using Product -> Scheme -> Edit Scheme…
-
 ## Adding and Removing Syntax Nodes
 
 The files containing the definition of all of the syntax nodes are available
-under the [SyntaxSupport][SyntaxSupport] directory. These files
+under the [SyntaxSupport](SyntaxSupport) directory. These files
 are roughly divided according to broad syntactic categories in the Swift
 programming language. That is, the syntax nodes for classes, structs, and actors
-are defined in `DeclNodes.py`, while the syntax nodes for string literals, 
-arrays, and tuples is defined in `ExprNodes.py`.
+are defined in `DeclNodes.swift`, while the syntax nodes for string literals, 
+arrays, and tuples is defined in `ExprNodes.swift`.
 
 To add a node to these files, it can be helpful to copy an existing node and 
 alter its definition to suit the needs of the new syntax being defined. A syntax
-node consists of a name, a kind, and a list of child nodes. The name of a node
-not only identifies it uniquely to Swift Syntax, it also provides a handle that
-other nodes can use to refer to it. The kind of a syntax node defines the
-class of syntax the node belongs to. All nodes are at least of the `Syntax`
+node consists of a kind (which also defines the node’s name), a base kind, and a list of 
+child nodes. The base kind of a syntax node defines the class of syntax the node belongs to. 
+All nodes are at least of the `Syntax`
 kind, though some nodes may have a more specific kind like `Stmt` for
 statements or `Expr` for expressions. The SwiftSyntax library expands these
 kinds into protocol conformances and allows for casting strongly typed syntax
@@ -45,33 +41,29 @@ nodes among these categories for easier processing.
 The node for a source file is reproduced below:
 
 ```swift
-  Node(
-    name: "SourceFile",
-    nameForDiagnostics: "source file",
-    kind: "Syntax",
-    traits: [
-      "WithStatements"
-    ],
-    parserFunction: "parseSourceFile",
-    children: [
-      Child(
-        name: "Statements",
-        kind: .collection(kind: "CodeBlockItemList", collectionElementName: "Statement")
-      ),
-      Child(
-        name: "EOFToken",
-        kind: .node(kind: "EOFToken")
-      ),
-    ]
-  ),
-
+Node(
+  kind: .sourceFile,
+  base: .syntax,
+  nameForDiagnostics: "source file",
+  parserFunction: "parseSourceFile",
+  traits: ["WithStatements"],
+  children: [
+    Child(
+      name: "Statements",
+      kind: .collection(kind: .codeBlockItemList, collectionElementName: "Statement")
+    ),
+    Child(
+      name: "EndOfFileToken",
+      deprecatedName: "EOFToken",
+      kind: .token(choices: [.token(tokenKind: "EndOfFileToken")])
+    ),
+  ]
+)
 ```
 
 ## Committing Changes
 
-When it is time to commit changes to the Swift Syntax repository, most cases
-of adding syntax will require a single PR to swift-syntax. Added
-syntactic elements will require corresponding changes to the included 
+Added syntactic elements will require corresponding changes to the included 
 SwiftParser library. For an introduction on parsing Swift nodes, see 
 [the article on Parsing Basics][ParserBasics].
 
@@ -82,21 +74,10 @@ SwiftParser library. For an introduction on parsing Swift nodes, see
 
 When updating nodes, certain clients of SwiftSyntax that are relying upon those
 nodes will need to be changed in tandem. For example, the 
-[swift-stress-tester][swift-stress-tester] uses SwiftSyntax, and the CI/CD
+[swift-stress-tester][swift-stress-tester] uses SwiftSyntax, and the CI
 system will not allow changes to SwiftSyntax that break `swift-stress-tester`
 without a paired change to that repository.
 
-When adding nodes or removing existing nodes, it is often the case that you 
-will need a paired PR to the [Swift Compiler repository][Swiftc] as well. This
-step currently involves some amount of duplication with the SwiftParser library
-and is a much more involved process. [The Swift Forums][CompilerDev] are a 
-great source for guidance on how to extend the C++ compiler to accommodate new 
-syntax and semantics for the Swift programming language.
-
-[LiterateProgramming]: https://en.wikipedia.org/wiki/Literate_programming
-[SwiftToolchains]: https://www.swift.org/download/
 [SyntaxSupport]: https://github.com/apple/swift-syntax/tree/main/CodeGeneration/Sources/SyntaxSupport
 [swift-stress-tester]: https://github.com/apple/swift-stress-tester
-[Swiftc]: https://github.com/apple/swift
 [ParserBasics]: https://github.com/apple/swift-syntax/tree/main/Sources/SwiftParser/SwiftParser.docc/ParsingBasics.md
-[CompilerDev]: https://forums.swift.org/c/development/compiler/