Merge branch 'ps/the-index-is-no-more'

The singleton index_state instance "the_index" has been eliminated by always instantiating "the_repository" and replacing references to "the_index" with references to its .index member. * ps/the-index-is-no-more: repository: drop `initialize_the_repository()` repository: drop `the_index` variable builtin/clone: stop using `the_index` repository: initialize index in `repo_init()` builtin: stop using `the_index` t/helper: stop using `the_index`