patch: document the section about import/export

patch: move import/export wrapping close to the function definition This gather similar logic together.

discovery: move all setup into a 'modsetup' function The various wrappings are moved into a function that live in the module and the function is now properly called during 'uisetup'.

revset: add a ui argument to 'modsetup' This is a gratuitous change for consistency with the function that use it.

revset: run 'modsetup' at uisetup time We are slowly moving away from module time wrapping. These thing should be done in the dedicated 'setup' method called by Mercurial.

destination: rename 'setupdest' to 'modsetup' the topic.revset module use 'modsetup' as a name for its setup function. It looks like a good name, lets unify names toward that.

destination: document 'setupdest' Let's make the role of this function clear.

destination: add a ui argument to 'setupdest' This is a gratuitous change for consistency.

destination: make sure 'setupdest' is the latest function in the module Let's introduce some consistency, end of module seems fine.

topicmap: move to new style import This unify with the new core Mercurial usage and this will make future changes to the imports easier to track.