Add the grammar to the reference manual, since the new docs don't
have the feature of putting all the small EBNF snippets together
into one big file.
diff --git a/Doc/reference/index.rst b/Doc/reference/index.rst
index 18bf053..adb5420 100644
--- a/Doc/reference/index.rst
+++ b/Doc/reference/index.rst
@@ -27,4 +27,4 @@
    simple_stmts.rst
    compound_stmts.rst
    toplevel_components.rst
-
+   grammar.rst