patch 8.2.1395: Vim9: no error if declaring a funcref with lower case letter

Problem:    Vim9: no error if declaring a funcref with a lower case letter.
Solution:   Check the name after the type is inferred. Fix confusing name.
diff --git a/src/testdir/test_vim9_script.vim b/src/testdir/test_vim9_script.vim
index 10706b1..eedce32 100644
--- a/src/testdir/test_vim9_script.vim
+++ b/src/testdir/test_vim9_script.vim
@@ -28,6 +28,7 @@
   call CheckDefFailure(['let x:string'], 'E1069:')
   call CheckDefFailure(['let x:string = "x"'], 'E1069:')
   call CheckDefFailure(['let a:string = "x"'], 'E1069:')
+  call CheckDefFailure(['let lambda = {-> "lambda"}'], 'E704:')
 
   let nr: number = 1234
   call CheckDefFailure(['let nr: number = "asdf"'], 'E1013:')