In the process tree also show children if the we match the parent.
This is somewhat the opposite of recursive filtering ("show parent if a
child is shown"). Example:
 A
 |-B
 | |-D
 | |-E
 |-C
Currently if you search for "E", A, B and E will be shown, this is not
changed by this commit and the effect of the recursive filtering.
But if the filter is "B", only A and B will be shown.
With this commit A, B, D and E are shown.