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/grammar.rst b/Doc/reference/grammar.rst
new file mode 100644
index 0000000..83d0f85
--- /dev/null
+++ b/Doc/reference/grammar.rst
@@ -0,0 +1,7 @@
+Full Grammar specification
+==========================
+
+This is the full Python grammar, as it is read by the parser generator and used
+to parse Python source files:
+
+.. literalinclude:: ../../Grammar/Grammar