help: provide a more helpful message when no keyword are matched Before this changeset, when no topic were matching the provided keyword ( in command such as `hg help --keyword babar`) the output was empty. This is confusing and unhelpful for new users seeking assistance in the help. We now display: $ hg help --keyword babar abort: no matches (try "hg help" for a list of topics) This send users in a new direction where they may find what they are looking for.

revsetbenchmark: use optparse to retrieve argument We need more flexibility. For example we'll want to run the benchmark on other repository.

revsetbenchmark: add a usage message when no arguments are passed This increase the odd someone who didn't wrote will it find out how to use this script.

revsetbenchmark: add `::tip and draft()` to the canonical list The want to test element on different side of the iterators.

revset: cosmetic changes in spanset range comparison We use the python syntax for range comparison: `a < x < c`. This is shorter, more readable and less error prone. This comparison escaped the cleanup make in e2031c8ca4f8

revset: drop spanset._contained All its users inlined it for performance reasons. (See 1d7a2771aa36 and e2031c8ca4f8)