tests: add (?) flag for optional lines
When the test engine fails to match output on a line marked with (?),
it will simply continue to the next expected line and try again. This
allows simplifying tests that have either version-specific or
non-fixed behavior, for instance:
$ coin-flip
heads (?)
tails (?)
(There's no form of back-tracking attempted, so optional matches
should be specific.)
default = 'shortlog'
shortlog = "'raw' is not a browsable style"
changelog = changelog.tmpl
changelogentry = logentry.tmpl
search = search.tmpl
searchentry = logentry.tmpl
mimetype = 'text/plain; charset={encoding}'
header = ''
footer = ''
changeset = changeset.tmpl
difflineplus = '{line}'
difflineminus = '{line}'
difflineat = '{line}'
diffline = '{line}'
changesetparent = '# Parent {node}'
changesetchild = '# Child {node}'
filenodelink = ''
filenolink = ''
fileline = '{line}'
diffblock = '{lines}'
filediff = filediff.tmpl
fileannotate = fileannotate.tmpl
annotateline = '{author|user}@{rev}: {line}'
manifest = manifest.tmpl
direntry = 'drwxr-xr-x {basename}\n'
fileentry = '{permissions|permissions} {size} {basename}\n'
index = index.tmpl
notfound = notfound.tmpl
error = error.tmpl
indexentry = '{url}\n'
tags = '{entries%tagentry}'
tagentry = '{tag} {node}\n'
bookmarks = '{entries%bookmarkentry}'
bookmarkentry = '{bookmark} {node}\n'
branches = '{entries%branchentry}'
branchentry = '{branch} {node} {status}\n'
graph = graph.tmpl
graphnode = graphnode.tmpl
graphedge = graphedge.tmpl
bookmarkname = 'bookmark: {name}\n'
branchname = 'branch: {name}\n'
tagname = 'tag: {name}\n'