Which Mesoamerican civilization's writing was largely destroyed by one bishop in one night?

The Maya. In July 1562, at Maní in Yucatán, Diego de Landa held an auto-da-fé and burned the accumulated books of the region - he records destroying twenty-seven, and notes with some puzzlement that the Maya were extraordinarily distressed by it.

Four codices survive worldwide. Everything else is inscription on stone and pottery, which is why the decipherment took until the late twentieth century and why enormous stretches of Maya history are simply unrecoverable - the books were bark paper folded like a screen, holding astronomy, ritual calendars and dynastic records.

The bitter part is that Landa also wrote the key. Recalled to Spain to answer for the brutality of his campaign, he composed an account of Maya life that included what he thought was an alphabet, dictated by an informant. It was not an alphabet - the script is largely syllabic, and his informant appears to have been giving him the Maya names of Spanish letters - but when a Russian scholar, Yuri Knorozov, worked that out in 1952, Landa's confused list became the way in. The man who burned the library preserved the means of reading it.