DOC: gcd/2 and lcm/2 are not operators.

man/builtin.doc

@@ -8656,13 +8656,13 @@ Rational number division. This function is only available if
 SWI-Prolog has been compiled with rational number support. See
 \secref{rational} for details.
 
-    \infixfunction{gcd}{+IntExpr1}{+IntExpr2}
+    \function{gcd}{2}{+IntExpr1, +IntExpr2}
 Result is the greatest common divisor of \arg{IntExpr1} and
 \arg{IntExpr2}. The GCD is always a positive integer. If either
 expression evaluates to zero the GCD is the result of the other
 expression.
 
-    \infixfunction{lcm}{+IntExpr1}{+IntExpr2}
+    \function{lcm}{2}{+IntExpr1, +IntExpr2}
 Result is the least common multiple of \arg{IntExpr1},
 \arg{IntExpr2}.\bug{If the system is compiled for bounded integers only
 \funcref{lcm}{2} produces an integer overflow if the product of the two