This should help new users off to a better start with the addition of
more sensible saved searches and default shortcut keys. Most existing
users have probably customized this variable and won't be affected.
This patch removes trailing spaces in notmuch-hello view.
A side effect of this change is that tag/query buttons no longer
include a space at the end. This means that pressing RET when the
point is at the first character after the tag/query button no longer
works (note that this is the standard behavior for buttons). We may
change this behavior in the future (without adding trailing spaces
back) if people would find this change inconvenient.