rebase: handle bookmarks matching revset function names (issue3950)

We handled these correctly with all rev-specifying options except,
somehow, -r/--rev.

--HG--
branch : stable
extra : rebase_source : 097c6d9d7a7d62ee243c64baf29b3a54b25cc6e4
histedit: add description about basic histedit function to command help

Before this patch, there is no explicit description that histedit
edits changesets between specified ancestor and the parent of the
working directory: users may notice it by error message "REV is not an
ancestor of working directory".

This patch adds description about basic histedit function to command
help of it.

This patch uses term "ancestor" instead of "parent", because it seems
to be more suitable, and almost all (error) messages already use it.

--HG--
branch : stable
extra : rebase_source : 98d2c8f93dd3f495572c97ebda31e58c2255d169
histedit: add description about "histedit --outgoing" to command help

Before this patch, there is no explicit description that argument is
treated as the URL of the destination repository when "--outgoing" is
specified.

This patch adds description about "histedit --outgoing" to command
help of it.

--HG--
branch : stable
extra : rebase_source : 8d5ca4448c35e45df8dcd89b28bd6d9b45cb3487