Fix trailing whitespace after some function decls.

Author: dabelknap

Sources/SwiftFormatPrettyPrint/TokenStreamCreator.swift

@@ -835,7 +835,11 @@ private final class TokenStreamCreator: SyntaxVisitor {
       node.genericWhereClause?.firstToken,
       tokens: .break, .open(.inconsistent, 0), .break(size: 0), .open(.consistent, 0)
     )
-    after(node.genericWhereClause?.lastToken, tokens: .break, .close, .close)
+    if node.body != nil {
+      after(node.genericWhereClause?.lastToken, tokens: .break, .close, .close)
+    } else {
+      after(node.genericWhereClause?.lastToken, tokens: .close, .close)
+    }
 
     if let body = node.body {
       if node.genericWhereClause == nil {

Tests/SwiftFormatPrettyPrintTests/FunctionDeclTests.swift

@@ -301,6 +301,36 @@ public class FunctionDeclTests: PrettyPrintTestCase {
     assertPrettyPrintEqual(input: input, expected: expected, linelength: 50)
   }
 
+  public func testBodilessFunctionDecl() {
+    let input =
+      """
+      func myFun()
+
+      func myFun(arg1: Int)
+
+      func myFun() -> Int
+
+      func myFun<T>(arg1: Int)
+
+      func myFun<T>(arg1: Int) where T: S
+      """
+
+    let expected =
+      """
+      func myFun()
+
+      func myFun(arg1: Int)
+
+      func myFun() -> Int
+
+      func myFun<T>(arg1: Int)
+
+      func myFun<T>(arg1: Int) where T: S
+
+      """
+
+    assertPrettyPrintEqual(input: input, expected: expected, linelength: 50)
+  }
 
   public func testFunctionFullWrap() {
     let input =