[intro] we should remove all "shall" from the clause

[xmh0511]

Full name of submitter (unless configured in github; will be published with the issue): Jim X

The consensus is that "shall" implies we impose requirements on the user's code. Instead, we use a common statement for imposing requirements on language/implementations.

A conforming implementation executing a well-formed program shall produce the observable behavior of the defined prefix of one of the possible executions of the corresponding instance of the abstract machine with the same program and the same input.

This requirement is obviously imposed on the implementations, so "shall" should be removed. Furthermore, the rules in the whole clause [intro] are all applied to implementations, so we should de-shall.

Suggested Resolution:

To make the consensus consistently apply to the whole standard, we should remove "shall" in [intro].

[safocl]

It seems to me that the main principles of the standard's provisions have been omitted again ([intro#compliance.general-2])

[jensmaurer]

[intro] specifies requirements on conforming implementations. The "shall" is appropriate there, and is a "shall" according to the ISO Directives.

[xmh0511]

@jensmaurer However, we did express the consensus in #823 (comment)

just use regular indicative voice for general descriptions (requirements) on the language (and thus the implementation) itself. This keeps the standard readable.

[intro] does impose requirement on the implementations anyway.

[jensmaurer]

Yes, [intro] is the exception: It's the highest-level abstraction in the standard, and that's where we want to tie into ISO Directives phrasing more than anywhere else.