Deprecated isImplicit

This property seems to be pretty useless and probably dates back to a completely different design of the syntax tree where implicit nodes were a thing.

Author: ahoppen

Sources/SwiftSyntax/Syntax.swift

@@ -624,6 +624,7 @@ public extension SyntaxProtocol {
 public extension SyntaxProtocol {
   /// When isImplicit is true, the syntax node doesn't include any
   /// underlying tokens, e.g. an empty CodeBlockItemList.
+  @available(*, deprecated, message: "Check children(viewMode: .all).isEmpty instead")
   var isImplicit: Bool {
     return raw.isEmpty
   }

Tests/SwiftSyntaxTest/AbsolutePositionTests.swift

@@ -85,7 +85,6 @@ public class AbsolutePositionTests: XCTestCase {
         + state.trailingTrivia.sourceLength.utf8Length
         + state.byteSizeAfterTrimmingTrivia
     )
-    XCTAssertFalse(root.statements.isImplicit)
 
     // Test Node trivia setters and getters
 
@@ -122,11 +121,6 @@ public class AbsolutePositionTests: XCTestCase {
     XCTAssertEqual([.verticalTabs(4)], modifiedStatements2.trailingTrivia)
   }
 
-  public func testImplicit() {
-    let root = self.createSourceFile(0)
-    XCTAssertTrue(root.statements.isImplicit)
-  }
-
   public func testWithoutSourceFileRoot() {
     let item = CodeBlockItemSyntax(
       item: .init(