Backport from 3.2: fix formatting of syntax description of function definition.
diff --git a/Doc/reference/compound_stmts.rst b/Doc/reference/compound_stmts.rst
index e98e261..a86eb11 100644
--- a/Doc/reference/compound_stmts.rst
+++ b/Doc/reference/compound_stmts.rst
@@ -431,7 +431,7 @@
funcdef: "def" `funcname` "(" [`parameter_list`] ")" ":" `suite`
dotted_name: `identifier` ("." `identifier`)*
parameter_list: (`defparameter` ",")*
- : ( "*" `identifier` [, "**" `identifier`]
+ : ( "*" `identifier` ["," "**" `identifier`]
: | "**" `identifier`
: | `defparameter` [","] )
defparameter: `parameter` ["=" `expression`]