Change casting function to SyntaxEnum to as(SyntaxEnum.self)

SyntaxEnum was the only place that uses the asSyntaxEnum-style casting.
Make the syntax more consistent with the other as(Something.self)
casting functions.

Author: ahoppen

Sources/SwiftSyntax/Misc.swift.gyb

@@ -43,7 +43,7 @@ public extension Syntax {
   /// Retrieve the concretely typed node that this Syntax node wraps.
   /// This property is exposed for testing purposes only.
   var _asConcreteType: Any {
-    switch self.asSyntaxEnum {
+    switch self.as(SyntaxEnum.self) {
     case .token(let node):
       return node
     case .unknown(let node):

Sources/SwiftSyntax/SyntaxEnum.swift.gyb

@@ -34,7 +34,7 @@ public enum SyntaxEnum {
 
 public extension Syntax {
   /// Get an enum that can be used to exhaustively switch over all syntax nodes.
-  var asSyntaxEnum: SyntaxEnum {
+  func `as`(_: SyntaxEnum.Type) -> SyntaxEnum {
     switch raw.kind {
     case .token:
       return .token(TokenSyntax(self)!)

Sources/SwiftSyntax/gyb_generated/Misc.swift

@@ -1352,7 +1352,7 @@ public extension Syntax {
   /// Retrieve the concretely typed node that this Syntax node wraps.
   /// This property is exposed for testing purposes only.
   var _asConcreteType: Any {
-    switch self.asSyntaxEnum {
+    switch self.as(SyntaxEnum.self) {
     case .token(let node):
       return node
     case .unknown(let node):

Sources/SwiftSyntax/gyb_generated/SyntaxEnum.swift

@@ -246,7 +246,7 @@ public enum SyntaxEnum {
 
 public extension Syntax {
   /// Get an enum that can be used to exhaustively switch over all syntax nodes.
-  var asSyntaxEnum: SyntaxEnum {
+  func `as`(_: SyntaxEnum.Type) -> SyntaxEnum {
     switch raw.kind {
     case .token:
       return .token(TokenSyntax(self)!)