add is:obsolete as synonym of is:obsoleted
add is:obsolete as synonym of is:obsoleted

The help text for search was documenting is:obsolete, not
is:obsoleted.  Fix the code to match the help text, and
the help text to match the code.

Signed-off-by: Paolo Bonzini <69d3ebcf5ee4e7f05a50dc23cd96655b730804b4@redhat.com>

pvital/patchew,pvital/patchew,pvital/patchew,pvital/patchew