doc: vale fixups; clarifications clarify modal workflow, move bulk edit workflow from middle of edit item worflow to after. Clarify postfix expression use with Link items. Add rst() and markdown() to stext() and mark stext as depricated (maybe even this release cycle). More TAL examples. Refill some paragraphs to 65 character lines. Various other fixes pointed out by vale.

try:
    # Python 3+.
    from xmlrpc import client, server
    server.SimpleXMLRPCDispatcher
except (ImportError, AttributeError):
    # Python 2.
    import SimpleXMLRPCServer as server
    import xmlrpclib as client  # noqa: F401