[avr-chat] description of _delay_ms incorrectly refers to _us argument

[Britton Kerin]

This page:

   http://www.nongnu.org/avr-libc/user-manual/group__util__delay.html

Contains this in the description of _delay_ms():

  Conversion of __us into clock cycles may not always result in integer. By
  default, the clock cycles rounded up to next integer. This ensures that
  the user gets atleast __us microseconds of delay.

That looks wrong because the argument to _delay_ms() is named __ms, not __us.

Britton