cmd/gofmt: fix typo in comment

Author: rillig

src/cmd/gofmt/rewrite.go

@@ -199,7 +199,7 @@ func match(m map[string]reflect.Value, pattern, val reflect.Value) bool {
 		// object pointers and token positions always match
 		return true
 	case callExprType:
-		// For calls, the Ellipsis fields (token.Position) must
+		// For calls, the Ellipsis fields (token.Pos) must
 		// match since that is how f(x) and f(x...) are different.
 		// Check them here but fall through for the remaining fields.
 		p := pattern.Interface().(*ast.CallExpr)