Update non-normative section on mapping messages to scenarios

[kleihan]

A subsection of Chapter 3.11 Workflow currently has the following text, defined as non-normative.

3.11.1.1 Mapping a message to a scenario

This section is non-normative.

The task of mapping an actual received FIX message to a scenario declaration in Orchestra is left to implementations. The first level of matching is on the msgType attribute with the FIX MsgType(35) field. However, that message type may have several scenarios. Pattern matching strategies might include comparing a message to expected required fields, mapping values of a distinguishing field like ExecType(150) to its code set literals, and so forth.

Version 1.1 RC1 adds a <when>element to message definition to define an expression for a mapping of a message to a scenario. This should be reflected in the spec and is normative.

Propose to also remove the current text as it is specific to FIX messages.