tests: add -k to test scripts matching keywords
argument is a space-separated list of keywords that are searched for
in the name and body of each test. This makes it easy to run only
tests related to tags, hgweb, revert, etc. (eg -k "tag hgweb revert").
% no bookmarks
no bookmarks set
% set bookmark X
% list bookmarks
* X -1:000000000000
% update to bookmark X
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% list bookmarks
* X -1:000000000000
% rename
% list bookmarks
* Z -1:000000000000
% new bookmark Y
% list bookmarks
* Y -1:000000000000
Z -1:000000000000
% commit
% list bookmarks
* Y 0:719295282060
Z -1:000000000000
% delete bookmarks
% list bookmarks
no bookmarks set
% update to tip
0 files updated, 0 files merged, 0 files removed, 0 files unresolved