rustdoc: nodemap doc refreshing Not pretending to be comprehensive. - correcting some inconsistencies - adding a few missing doc-comments - adding more cross references (in some cases it's right beside the current documentation item, but it will nevertheless also be useful, because `rustdoc` will warn us if inconsistencies arise).

rustdoc: fixed or introduced crossrefs in nodemap.rs

rustdoc: summary line for hg_path_to_os_string The main motivation of this change is to avoid the TODO being the summary line, even though this leads to a pretty obvious summary. Then doc-comments for the other functions are introduced for consistency.

rustdoc: wording for checkexec Notably separating the summary line for correct display at module level.

rustdoc: fixed warnings about links This is the minimal fix making those that actually were supposed to be links to work (including in private items).

rust-changelog: introduce ChangelogEntry parent entries accessors Straightforwards now that lifetimes are explicit in `RevlogEntry` parent accessors.

rust-revlog: fix lifetime problem for RevlogEntry parent entries accessors Without this, the lifetime of the result is equated to the lifetime of the `self` reference, preventing callers, e.g., to take a `RevlogEntry` and return its `p1_entry()`, as it looks like returning something that does not outlive the *reference to* the `RevlogEntry`.

rust-revlog: explicit naming for `RevlogEntry` lifetime This matches what has been done in `revlog::changelog::ChangelogRevisionData`, and has the advantage of making things clearer when we introduce other, shorter lived lifetimes.

rust-changelog: introducing an intermediate `ChangelogEntry` Before this change, client code needing to extract, e.g, the Node ID and the description from a changeset had no other choice than calling both `entry_for_rev()` and `data_for_rev()`. This duplicates some (limited) computation, and more importantly imposes bad hygiene for client code: at some point of developement, the client code would have to pass over both entry and data in its internal layers, which at some point of development would raise the question whether they are consistent. We introduce the intermediate `ChangelogEntry` from which both conversion to the generic `RevlogEntry` and extraction of `ChangelogRevisionData` are possible. It might grow some convenience methods in the future. We keep the `data_for_rev()` method of `Changelog` for compatibility, pointing users at the more powerful alternative.

rust-changelog: added a test for `NULL_REVISION` special case The result is due to `Revlog.get_rev_data()` returning an empty byte string for `NULL_REVISION`, followed by special case for emtpty byte strings in `ChangelogRevisionData::new()`.

rust-changelog: made doc-comments more consistent The most important is the one about `data_for_rev`, that looked like a copy-paste leftover (got me confused first time I read this code, before I actually learned there were both `Entry` and RevisionData`. In the comment for the `struct`, "changelog" was probably more about the format in general (as documented elsewhere) than as an identifier. Some of the "Return something" had "of", half had "for".

extras: re-use Projection from jaraco.collections

extras: expose 'retained_extras' for extensions to extend

extras: extract function for projecting names from a gettable object

hgweb: add "children" into the JSON template for a changeset The children are shown in the HTML templates, so I don’t see a reason against including them in the JSON template as well.

branching: merge stable into default

help: fix formatting for http config section

branching: merge stable into default

fastexport: rework newline logic Newlines should only be added when otherwise the stream would look weird without them (on blobs), therefore they are the exception. Flip the logic so they are added, not skipped.

encoding: avoid quadratic time complexity when json-encoding non-UTF8 strings Apparently the code uses "+=" with a bytes object, which is linear-time, so the whole encoding is quadratic-time. This patch makes us use a bytearray object, instead, which has a(n amortized-)constant-time append operation. The encoding is still not particularly fast, but at least a 10MB file takes tens of seconds, not many hours to encode.

bundle: prevent implicite bundling of internal changeset Now that the two mains source of on-disk bundle are preventing the inclusion of internal changesets in their bundling. We can add a lower level check that would prevent any other leakage of internal-phase changesets. We keep the door open to some usage, like the temporary bundle using during strip for example.

bundle: abort if the user request bundling of internal changesets See inline comments for details.

strip: do now include internal changeset in the strip backup See inline comment for details.

revset: add `_internal()` predicate This predicate help core code to select internal changeset (in the internal phase).