revert: add transaction processing chapter with internals info

Bruce Momjian <bruce@momjian.us>

Commit: af6a76931634780fd5a67f2e1dee84a269e1f14a
Author: Bruce Momjian <bruce@momjian.us>
Date: 2022-12-01T15:45:08Z
Releases: 12.14
revert:  add transaction processing chapter with internals info

This doc patch (master hash 66bc9d2d3e) was decided to be too
significant for backpatching, so reverted in all but master.  Also fix
SGML file header comment in master.

Reported-by:  	Peter Eisentraut

Discussion: https://postgr.es/m/c6304b19-6ff7-f3af-0148-cf7aa7e2fbfd@enterprisedb.com

Backpatch-through: 11

Files

Documentation touched