Fix Issue 19289 - std.range.transposed with enforceNotJagged not throwing

[ghost]

see https://forum.dlang.org/post/tmqppgmuevecltmxygrd@forum.dlang.org

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Bugzilla references

Auto-close	Bugzilla	Severity	Description
✓	19289	normal	std.range.transposed with enforceNotJagged not throwing

Testing this PR locally

If you don't have a local development environment setup, you can use Digger to test this PR:

dub fetch digger
dub run digger -- build "master + phobos#6723"

[ghost]

This needs to come with a unittest that assertThrown.

[ghost]

LGTM, assuming no changelog is needed otherwise open an issue and reference it in the git commit, see guide i don't remember where.

[n8sh]

_input.front's length is unnecessarily enforced to be equal to itself.

[ghost]

I just copied the code from transverse. If you've got an idea how to remove this redundancy you should do this at transverse as well.

[n8sh]

Fair.

[n8sh]

Linux_64_32 failure appears unrelated.

[n8sh]

Add a reference to an issue number and this can be merged.