topics: take logic to parse username to a separate function In next patch we will be adding support to `hg stack` to show users, and this logic will be required there too. So let's take it out in a separate function.

changelog: fix a typo in the changelog There is probably many others but that one is fixed now.

caches: switch to 'auto' warming by default This options seems good let us make it the default.

caches: add a 'auto' option for obshashrange cache warming This option will only warm the cache when used as a server.

caches: extract some config reading in 'shouldwarmcache'

caches: pass the transaction to the "shouldwarncache" logic This will allow to have smarter mode about cache warming (eg: only warm them for server transaction.

caches: record 'desc' attribute on transaction This is useful to know if a transaction if server side or not.