docs: prefer the awk+sh TAP driver over the perl one We had completed our shell+awk implementation of the TAP driver months ago, but never documented it in the manual, continuing to document only the "prototype" written in perl instead. Time to fix this, before the 1.12 release. * doc/automake.texi (Use TAP with the Automake test harness): Now we document the use of the awk+shell implementation of our TAP driver, rather than of the perl one. * tests/tap-doc2.test: Adjust to use the shell+awk implementation of the TAP driver.