Add pub(crate) visibility

[guipublic]

Problem

We support the pub attribute when defining a function, so that the function is visible everywhere externally and internally.

We could extend it with the pub(crate) notation which would allow the function to be used inside the crate, but not in an external crate.

Happy Case

pub(crate) makes a function visible within the current crate.

Alternatives Considered

No response

Additional Context

No response

Would you like to submit a PR for this Issue?

No

Support Needs

No response

[kevaundray]

Also tagging along pub(crate) and pub for structures, but we may want this in another issue