[3.10] bpo-44305: Improve syntax error for try blocks without except or finally (GH-26523) (GH-26524)

(cherry picked from commit b250f89bb7e05e72a4641d44b988866b919575db)

Co-authored-by: Pablo Galindo <Pablogsal@gmail.com>
diff --git a/Grammar/python.gram b/Grammar/python.gram
index 8b5d921..d0f9bb0 100644
--- a/Grammar/python.gram
+++ b/Grammar/python.gram
@@ -964,6 +964,7 @@
 invalid_try_stmt:
     | a='try' ':' NEWLINE !INDENT {
         RAISE_INDENTATION_ERROR("expected an indented block after 'try' statement on line %d", a->lineno) }
+    | 'try' ':' block !('except' | 'finally') { RAISE_SYNTAX_ERROR("expected 'except' or 'finally' block") }
 invalid_except_stmt:
     | 'except' a=expression ',' expressions ['as' NAME ] ':' {
         RAISE_SYNTAX_ERROR_STARTING_FROM(a, "multiple exception types must be parenthesized") }