webcommands: document "changeset" web command

webcommands: document "tags" web command

webcommands: document "bookmarks" web command

webcommands: document "branches" web command

webcommands: document "help" web command

help: add web commands to help documentation The capabilities and URL endpoints of the hgweb server can currently only be inferred by looking at links in `hg serve` output or by reading the source code. I've frequently found myself wanting to quickly see what URLs and capabilities are available. This patch teaches the help system how to display information about web commands and their URLs. Using a mechanism similar to revsets, templates, etc, we can now iterate over the docstrings of registered web command functions and display them in the help output. Unfortunately, web commands don't currently have docstrings, so the output is currently empty. This will be addressed in the following patches. I apologize for the patch bomb.

help.hgweb: add a section describing URLs and common parameters The behavior of hgweb's URLs isn't documented anywhere inside Mercurial. Let's start to change that.

webcommands: move help import into help command handler A subsequent patch will introduce an import cycle between mercurial.help and mercurial.hgweb.webcommands. Break the cycle by moving the import of mercurial.help into the web command that actually needs it.

webcommands: define a dict of available commands This will be used to hook web commands up to the help system. It also makes web commands work similarly as CLI commands.

webcommands: define web commands using a decorator Other parts of Mercurial have evolved to use decorators to declare commands or handlers. This patch gives the same treatment to web commands.