exchange: make clonebundleprefers non-experimental In preparation for making the feature enabled by default.

clonebundles: remove advertisement of feature I screwed up. When clone bundles is enabled on the server and a compatible client without the feature enabled clones, the server sends down an advertisement saying to enable the feature. The server creates the message which is printed verbatim on the client as an "output" part. There are 2 problems: 1) The message doesn't respect the client's localization 2) The message contains a reference to the "experimental.clonebundles" option. Since clone bundles is about to be marked as non-experimental and the goal of the advertisement was to encourage clients to test the experimental feature, let's just remove the broken advertisement since it no longer serves a purpose.

changegroup: remove now-unused 'wasempty' variable and parameter

treemanifests: set bundle2 part parameter indicating treemanifest By adding a mandatory 'treemanifest' parameter in the bundle2 part, we make it possible for the recipient to set repo requirements before the manifest revlog is accessed.

docchecker: scan for missing space before :hg:

tests: run docchecker in gendoc.t

tests: move gendoc.t runrst comment next to runrst

docchecker: introduce a way to check for poor markup Specifically, :hg:`foo 'bar baz'` when rendered by `hg help` results in: 'hg foo 'bar baz'' ... which is hard to read. We encourage :hg:`foo "bar baz"` instead.