mercurial/help/multirevs.txt

extensions: allow extending command synopsis and docstring

Mercurial uses a synopsis string and the docstring of a command for the
command's help output. Today  there is no way for an extension that adds
functionality to a command to extend either of these help strings.

This patch enables appending to both the doctring and the synopsis, and adds
a test for this functionality. Example usage is shown in the test and is also
described in the docstring of extensions.wrapcommand().

When Mercurial accepts more than one revision, they may be specified
individually, or provided as a topologically continuous range,
separated by the ":" character.

The syntax of range notation is [BEGIN]:[END], where BEGIN and END are
revision identifiers. Both BEGIN and END are optional. If BEGIN is not
specified, it defaults to revision number 0. If END is not specified,
it defaults to the tip. The range ":" thus means "all revisions".

If BEGIN is greater than END, revisions are treated in reverse order.

A range acts as a closed interval. This means that a range of 3:5
gives 3, 4 and 5. Similarly, a range of 9:6 gives 9, 8, 7, and 6.