patch 8.2.2575: Vim9: a function name with "->" in the next line doesn't work

Problem:    Vim9: a function name with "->" in the next line doesn't work.
Solution:   Recognize a function name by itself. (closes #7770)

src/testdir/test_vim9_cmd.vim

@@ -355,6 +355,25 @@ def Test_method_call_linebreak()
   END
   CheckDefAndScriptSuccess(lines)
 
+  lines =<< trim END
+      new
+      def Foo(): string
+        return 'the text'
+      enddef
+      def Bar(F: func): string
+        return F()
+      enddef
+      def Test()
+        Foo
+          ->Bar()
+          ->setline(1)
+      enddef
+      Test()
+      assert_equal('the text', getline(1))
+      bwipe!
+  END
+  CheckDefAndScriptSuccess(lines)
+
   lines =<< trim END
       new
       g:shortlist