C2MS11 — NUM-OF-[ITEMS] Should be Required

As part of C2MS11-14, which was already approved, there was a subtle inconsistency through its text and image changes. This issue is to capture the change for final submission of the documentation for C2MS 1.1.

In that issue, in the Configuration Status Message there is a field, NUM-OF-ASSOCS. It is marked optional in the diagram, but required in the text table.

In the Heartbeat Message, NUM-OF-SUBSCRIPTIONS is shown as optional, both in the diagram and in the text table.

In the Mnemonic Value Request Message, NUM-OF-MNEMONICS is shown as required, both in the diagram and in the text table.

In all cases throughout C2MS where there is a NUM-OF-[ITEMS] field, it should be required in the corresponding diagram and text table.

This is to align it with the obvious. The NUM-OF field indicates how many items are present in a set, such as MNEMONICS. If there are none, this field should simply be set to 0. However, if it were optional, that would mean that the field would either be present or set to 0. The former is preferred for clarity.