Don't allow --style and --template for hg update and hg merge.
The only way that changesets will be shown with these command is in an error
message when trying to update to an ambiguous branch name.
Is there an error message when trying to diff non-existing files?
found: No such file or directory
not: No such file or directory
Is there an error message when trying to add non-existing files?
found: No such file or directory
not: No such file or directory