Add documentation on BANK bit ignored if being set to 1.

Author: Red-M

adafruit_mcp230xx/mcp23017.py

@@ -253,7 +253,7 @@ def io_control(self):
         Bit 4 is whether SDA slew rate is enabled (1 = yes). Bit 5 is if I2C
         address pointer auto-increments (1 = no). Bit 6 is whether interrupt
         pins are internally connected (1 = yes). Bit 7 is whether registers
-        are all in one bank (1 = no).
+        are all in one bank (1 = no), this is silently ignored if set to `1`.
         """
         return self._read_u8(_MCP23017_IOCON)
 

adafruit_mcp230xx/mcp23s17.py

@@ -257,7 +257,7 @@ def io_control(self):
         Bit 4 is whether SDA slew rate is enabled (1 = yes). Bit 5 is if SPI
         address pointer auto-increments (1 = no). Bit 6 is whether interrupt
         pins are internally connected (1 = yes). Bit 7 is whether registers
-        are all in one bank (1 = no).
+        are all in one bank (1 = no), this is silently ignored if set to `1`.
         """
         return self._read_u8(_MCP23S17_IOCON)