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 docutils gettext
$ $TESTDIR/check-gendoc de
checking for parse errors
Die Dateien werden dem Projektarchiv beim n\xc3\xa4chsten \xc3\x9cbernehmen (commit) hinzugef\xc3\xbcgt. Um dies vorher r\xc3\xbcckg\xc3\xa4ngig zu machen, siehe:hg:`forget`. (esc)
warning: please have a space before :hg: