[committed] docs: Fix inconsistent example predicate name

[Andrew Carlotti via Gcc-patches]

It is unclear why the example C function was renamed to
`commutative_integer_operator` as part of ec8e098d in 2004, while the
text and the example md were both left as `commutative_operator`. The
latter name appears to be more accurate, so revert the 2004 change.

Committed as obvious.

gcc/ChangeLog:

        * doc/md.texi: Fix inconsistent example name.

---

diff --git a/gcc/doc/md.texi b/gcc/doc/md.texi
index 
78dc6d720700ca409677e44a34a60d4b7fceb046..cc28f868fc85b5148450548a54d69a39ecc4f03a
 100644
--- a/gcc/doc/md.texi
+++ b/gcc/doc/md.texi
@@ -377,7 +377,7 @@ commutative arithmetic operators of RTL and whose mode is 
@var{mode}:
 
 @smallexample
 int
-commutative_integer_operator (x, mode)
+commutative_operator (x, mode)
      rtx x;
      machine_mode mode;
 @{