log: move --graph and topo sort options to walkopts This is the last opts.get() found in getrevs(). It might be better to define an enum, but for now, it is just a string.

log: move miscellaneous filter/matcher options to walkopts Maybe this is the most uninteresting patch. I want to remove the dependency on untyped/unlabeled opts dict at all. I thought --no-merges and --only-merges could be merged into a single enum value, but actually they both can be set to filter out everything.

log: map --removed to walkopts.force_changelog_traversal This is the flag to forcibly enable the slowpath. I'm not sure if the slowpath parameter should be merged with this flag, so let's keep it as an immutable flag for now. I'll add another flag to support "grep --all-files". These two will be the flags which aren't directly mapped from the command-line options.

copies: rename some function to the new naming scheme We are about to introduce more function and more variants, it seems better to align everything on the new scheme, allowing `_` for clarify. We do this aligned in a dedicated changeset to make the next changesets simpler. Differential Revision: https://phab.mercurial-scm.org/D9113

changing-files: cache the various property We are going to start using them more having some basic caching would be good. The focus is not about performance yet, however avoid some easy N² trap seems reasonable. Differential Revision: https://phab.mercurial-scm.org/D9112

changing-files: always use `mark_touched` to update the touched set We use this function internally too because that will make cache invalidation simpler. Differential Revision: https://phab.mercurial-scm.org/D9111

changing-files: fix docstring As pointed by Pulkit Goyal. Differential Revision: https://phab.mercurial-scm.org/D9143