templater: abstract ifcontains() over wrapped types
This allows us to make .keytype private.
There's a minor BC that a hybrid dict/list of keytype=None now strictly
checks the type of the needle. For example, {ifcontains(rev, files)} no longer
matches a file named "1" at the rev=1. I made this change for consistency
with the get(dict, key) function. We can restore the old behavior by making
keytype=bytes the default if desired.
#require test-repo jshint hg10
$ . "$TESTDIR/helpers-testrepo.sh"
run jshint on all tracked files ending in .js except vendored dependencies
$ cd "`dirname "$TESTDIR"`"
$ testrepohg locate 'set:**.js' \
> 2>/dev/null \
> | xargs jshint