Allow parentheses surrounding ConditionalCommunications in ProcessBehaviourSequence

[GunnarMorrigan]

Currently their are no brackets allowed surrounding a ConditionalCommunications per

ProcessBehaviourSequence:
    ConditionalCommunications ( '>->' ProcessBehaviourLevel4 )?
;

Would be nice if this was changed for clearer and easier writing and reading of PROCDEFs.
Suggested change:

ProcessBehaviourSequence:
    ConditionalCommunications ( '>->' ProcessBehaviourLevel4 )?
    | '(' ConditionalCommunications ')' ( '>->' ProcessBehaviourLevel4 )?
;

This would allow the following:

while also still allowing no brackets:

PROCDEF example [In :: Int; Out :: Int] () ::=
    (
            In ? op | Out ? t1 [[ True ]]
        >->
            Out ! 2
    )
ENDDEF