tests: fix windows test failure in test-subrepo.t

--HG--
branch : stable
hgk: support the old way of getting the current Ttk theme (issue3808)

It seems like the API has changed somewhere around 8.5.7, so the preferred way
of getting the current theme is now [ttk::style theme use], while the
deprecated (but still working) is $::ttk::currentTheme.

--HG--
branch : stable
hgweb: make 'summary' work with hidden changesets (issue3810)

Since the 'summary' view used by e.g. gitweb and monoblue shows both a
changelog and a bookmarks list, the same changes are needed here as were
made to the 'changelog' and 'bookmarks' web commands (56ca4443a343 and
886936ecc21b, respectively).

--HG--
branch : stable
extra : amend_source : 3890503b0485e096d249c6b34bb3cc6bf2113202