Document purpose of closure in from_fn.rs more clearly

[hkBst]

partial fix for #135087 together with #135895

[rustbot]

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[joboet]

That's very tidy, good idea. Perhaps you could also add a link to the documentation for the next method? Otherwise this seems fine to me.

[joboet]

Thank you!
@bors r+ rollup

[bors]

📌 Commit 7328de0 has been approved by joboet

It is now in the queue for this repository.

[workingjubilee]

There was really no need to split this and #135895

There was definitely no need to split this into two commits. Please squash.

@bors r-

[hkBst]

squashed
@rustbot ready

[workingjubilee]

Thank you.

@bors r+ rollup

[bors]

📌 Commit d3cd832 has been approved by workingjubilee

It is now in the queue for this repository.