Add release notes

Author: Azoy

Release Notes/601.md

@@ -2,6 +2,10 @@
 
 ## New APIs
 
+- `GenericParameterSyntax` now has a new `specifier` property.
+  - Description: With the introduction of value generics, generic parameters can now be optionally preceded by either a `let` or an `each`. The `specifier` property captures the token representing which one was parsed.
+  - Pull Request: https://github.com/swiftlang/swift-syntax/pull/2785
+
 - `IntegerLiteralExprSyntax` and `FloatLiteralExprSyntax` now have a computed `representedLiteralValue` property.
   - Description: Allows retrieving the represented literal value when valid.
   - Issue: https://github.com/apple/swift-syntax/issues/405
@@ -27,6 +31,10 @@
 
 ## Deprecations
 
+- `GenericParameterSyntax` deprecated `eachKeyword` in favor of `specifier`
+  - Description: `specifier` is now used to grab either the `each` keyword for a generic parameter or the `let` keyword.
+  - Pull request: https://github.com/swiftlang/swift-syntax/pull/2785
+
 - `IncrementalEdit` deprecated in favor of `SourceEdit`
   - Description: `IncrementalEdit` is being dropped for `SourceEdit`. `SourceEdit` has deprecated compatibility layers to make it API-compatible with `IncrementalEdit`
   - Issue: https://github.com/apple/swift-syntax/issues/2532

Sources/SwiftParser/Declarations.swift

@@ -431,11 +431,9 @@ extension Parser {
       repeat {
         let attributes = self.parseAttributeList()
 
-        var specifier: Token? = nil
-
         // Parse the 'each' keyword for a type parameter pack 'each T' or a
         // 'let' keyword for a value parameter 'let N: Int'.
-        let specifier = self.consume(if: .keyword(.each), .keyword(.let))
+        var specifier = self.consume(if: .keyword(.each), .keyword(.let))
 
         let (unexpectedBetweenSpecifierAndName, name) = self.expectIdentifier(allowSelfOrCapitalSelfAsIdentifier: true)
         if attributes.isEmpty && specifier == nil && unexpectedBetweenSpecifierAndName == nil && name.isMissing