Clarify multiple instantiations and invocations for Issue 926

[MollyDream]

• We clarified that local stateful instantiations are evaluated in every instantiation of controls and parsers
• We clarified that local variable declarations are evaluated in every invocation of controls and parsers
• We added reference to direct type invocation in the two sections of invoking parsers (12.10) and controls (13.4)

Fixes #926

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[mihaibudiu]

@MollyDream if you use commit -s with your commits you will make the cla bot happy.

[MollyDream]

Ready for merging :)

[jnfoster]

We agreed to take this change at the April 2022 LDWG, after one more polishing pass.

[jnfoster]

Subsumed by #1243