[m-rev.] for review: burdened_module

[Julien Fischer]

On Tue, 25 Jan 2022, Zoltan Somogyi wrote:

> Introduce and use burdened_module.
> 
> compiler/module_imports.m:
>     Introduce the type burdened_module, as a version of burdened_aug_comp_unit
>     that contains only the parse_tree_module_src part of an augmented
>     compilation unit (i.e. the part *before* any augmentation).
>
>     Make some predicates operate on parse_tree_module_srcs instead of
>     aug_comp_units.

...

That's fine.

Julien.