f86f7ad5f2
The end goal is to eliminate `Map` altogether. I added a `hir_` prefix to all of them, that seemed simplest. The exceptions are `module_items` which became `hir_module_free_items` because there was already a `hir_module_items`, and `items` which became `hir_free_items` for consistency with `hir_module_free_items`.