This extends the `csd-filter-add` command to allow matching on window
titles as well, using a `csd-filter-add kind pattern` syntax. The
following kinds are supported:
* `title`, which matches window titles
* `app-id`, which matches app ids
Only exact matches are considered.
As an example following configuration applies client-side decorations to
all windows with the title 'asdf with spaces'.
riverctl csd-filter-add title 'asdf with spaces'
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