FLOOR.MATH has 3 parameters, show them in UI, tdf#69552 follow-up

(cherry picked from commit 7750dfcc)

Change-Id: I04a3990b90bd84c680df56ab6a5dc9eca575e696

sc/source/ui/src/scfuncs.src

@@ -4767,7 +4767,7 @@ Resource RID_SC_FUNCTION_DESCRIPTIONS1
             0;
             ID_FUNCTION_GRP_MATH;
             U2S( HID_FUNC_FLOOR_MATH );
-            2;  0;  1;  1;
+            3;  0;  1;  1;
             0;
         };
         String 2 // Name of Parameter 1